Fix buttons in Voting tab

[slaweet]

Expected behaviour

• The buttons are aligned
• Selecting delegates doesn't throw a warning

Actual behaviour

• The buttons are vertically misaligned
  
• Selecting delegates throws a warning into console because of the vote button

warning.js:35 Warning: Failed prop type: Invalid prop `label` of type `object` supplied to `Button`, expected `string`.
    in Button (created by RippledComponent)
    in RippledComponent (created by ThemedRippledComponent)
    in ThemedRippledComponent (created by ThemedThemed)
    in ThemedThemed (created by VotingHeader)
    in div (created by VotingHeader)
    in header (created by VotingHeader)
    in VotingHeader (created by Voting)
    in div (created by Voting)
    in Voting (created by Connect(Voting))
    in Connect(Voting) (created by Route)
    in Route (created by Route)
    in main (created by Route)
    in Route (created by PrivateRouteRender)
    in PrivateRouteRender (created by Connect(PrivateRouteRender))
    in Connect(PrivateRouteRender) (created by Route)
    in Route (created by withRouter(Connect(PrivateRouteRender)))
    in withRouter(Connect(PrivateRouteRender)) (created by App)
    in main (created by App)
    in div (created by App)
    in section (created by App)
    in span (created by OfflineWrapperComponent)
    in OfflineWrapperComponent (created by Connect(OfflineWrapperComponent))
    in Connect(OfflineWrapperComponent) (created by App)
    in App
    in I18nextProvider
    in Router (created by HashRouter)
    in HashRouter
    in Provider
printWarning @ warning.js:35
warning @ warning.js:59
checkReactTypeSpec @ checkReactTypeSpec.js:80
validatePropTypes @ ReactElementValidator.js:162
createElement @ ReactElementValidator.js:216
render @ Ripple.js:382
(anonymous) @ ReactCompositeComponent.js:795
measureLifeCyclePerf @ ReactCompositeComponent.js:75
_renderValidatedComponentWithoutOwnerOrContext @ ReactCompositeComponent.js:794
_renderValidatedComponent @ ReactCompositeComponent.js:821
_updateRenderedComponent @ ReactCompositeComponent.js:745
_performComponentUpdate @ ReactCompositeComponent.js:723
updateComponent @ ReactCompositeComponent.js:644
receiveComponent @ ReactCompositeComponent.js:546
receiveComponent @ ReactReconciler.js:124
_updateRenderedComponent @ ReactCompositeComponent.js:753
_performComponentUpdate @ ReactCompositeComponent.js:723
updateComponent @ ReactCompositeComponent.js:644
receiveComponent @ ReactCompositeComponent.js:546
receiveComponent @ ReactReconciler.js:124
_updateRenderedComponent @ ReactCompositeComponent.js:753
_performComponentUpdate @ ReactCompositeComponent.js:723
updateComponent @ ReactCompositeComponent.js:644
receiveComponent @ ReactCompositeComponent.js:546
receiveComponent @ ReactReconciler.js:124
updateChildren @ ReactChildReconciler.js:109
_reconcilerUpdateChildren @ ReactMultiChild.js:206
_updateChildren @ ReactMultiChild.js:310
updateChildren @ ReactMultiChild.js:297
_updateDOMChildren @ ReactDOMComponent.js:942
updateComponent @ ReactDOMComponent.js:760
receiveComponent @ ReactDOMComponent.js:722
receiveComponent @ ReactReconciler.js:124
updateChildren @ ReactChildReconciler.js:109
_reconcilerUpdateChildren @ ReactMultiChild.js:206
_updateChildren @ ReactMultiChild.js:310
updateChildren @ ReactMultiChild.js:297
_updateDOMChildren @ ReactDOMComponent.js:942
updateComponent @ ReactDOMComponent.js:760
receiveComponent @ ReactDOMComponent.js:722
receiveComponent @ ReactReconciler.js:124
_updateRenderedComponent @ ReactCompositeComponent.js:753
_performComponentUpdate @ ReactCompositeComponent.js:723
updateComponent @ ReactCompositeComponent.js:644
receiveComponent @ ReactCompositeComponent.js:546
receiveComponent @ ReactReconciler.js:124
updateChildren @ ReactChildReconciler.js:109
_reconcilerUpdateChildren @ ReactMultiChild.js:206
_updateChildren @ ReactMultiChild.js:310
updateChildren @ ReactMultiChild.js:297
_updateDOMChildren @ ReactDOMComponent.js:942
updateComponent @ ReactDOMComponent.js:760
receiveComponent @ ReactDOMComponent.js:722
receiveComponent @ ReactReconciler.js:124
_updateRenderedComponent @ ReactCompositeComponent.js:753
_performComponentUpdate @ ReactCompositeComponent.js:723
updateComponent @ ReactCompositeComponent.js:644
receiveComponent @ ReactCompositeComponent.js:546
receiveComponent @ ReactReconciler.js:124
_updateRenderedComponent @ ReactCompositeComponent.js:753
_performComponentUpdate @ ReactCompositeComponent.js:723
updateComponent @ ReactCompositeComponent.js:644
performUpdateIfNecessary @ ReactCompositeComponent.js:560
performUpdateIfNecessary @ ReactReconciler.js:156
runBatchedUpdates @ ReactUpdates.js:150
perform @ Transaction.js:143
perform @ Transaction.js:143
perform @ ReactUpdates.js:89
flushBatchedUpdates @ ReactUpdates.js:172
closeAll @ Transaction.js:209
perform @ Transaction.js:156
batchedUpdates @ ReactDefaultBatchingStrategy.js:62
batchedUpdates @ ReactUpdates.js:97
dispatchEvent @ ReactEventListener.js:147