Refactor CreateCrossSigningDialog (#28218)

* Refactor CreateCrossSigningDialog

 * Converts CreateCrossSigningDialog to a functional component
 * Pulls logic out to its own class
 * Updates usage of deprecated cross signing bootstrap method on client to be on the crypto object and updates test to match

Moved from https://github.com/element-hq/matrix-react-sdk/pull/131

* Add mock here too

* Use the right mock

* Remove duplicate mock

* Stray jest mock line

* Un-move mocks

* tsdoc

* Typo

Co-authored-by: Andy Balaam <andy.balaam@matrix.org>

---------

Co-authored-by: Andy Balaam <andy.balaam@matrix.org>

src/components/structures/MatrixChat.tsx

@@ -2088,6 +2088,7 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
         } else if (this.state.view === Views.E2E_SETUP) {
             view = (
                 <E2eSetup
+                    matrixClient={MatrixClientPeg.safeGet()}
                     onFinished={this.onCompleteSecurityE2eSetupFinished}
                     accountPassword={this.stores.accountPasswordStore.getPassword()}
                     tokenLogin={!!this.tokenLogin}