Use componentDidMount in place of componentWillMount where possible

This fixes a common React warning we see. Most of these components should be using constructors instead, however componentDidMount is just as good (and doesn't require converting most of these).

Conversion to classes will be done in a later stage of React warning fixes.

For https://github.com/vector-im/riot-web/issues/12877

src/components/views/dialogs/ConfirmUserActionDialog.js

@@ -55,7 +55,7 @@ export default createReactClass({
         askReason: false,
     }),
 
-    componentWillMount: function() {
+    componentDidMount: function() {
         this._reasonField = null;
     },
 

src/components/views/dialogs/RoomSettingsDialog.js

@@ -36,7 +36,7 @@ export default class RoomSettingsDialog extends React.Component {
         onFinished: PropTypes.func.isRequired,
     };
 
-    componentWillMount() {
+    componentDidMount() {
         this._dispatcherRef = dis.register(this._onAction);
     }
 

src/components/views/dialogs/RoomUpgradeDialog.js

@@ -30,7 +30,7 @@ export default createReactClass({
         onFinished: PropTypes.func.isRequired,
     },
 
-    componentWillMount: async function() {
+    componentDidMount: async function() {
         const recommended = await this.props.room.getRecommendedVersion();
         this._targetVersion = recommended.version;
         this.setState({busy: false});

src/components/views/dialogs/SetPasswordDialog.js

@@ -75,8 +75,8 @@ export default createReactClass({
         };
     },
 
-    componentWillMount: function() {
-        console.info('SetPasswordDialog component will mount');
+    componentDidMount: function() {
+        console.info('SetPasswordDialog component did mount');
     },
 
     _onPasswordChanged: function(res) {

src/components/views/dialogs/ShareDialog.js

@@ -121,7 +121,7 @@ export default class ShareDialog extends React.Component {
         });
     }
 
-    componentWillMount() {
+    componentDidMount() {
         if (this.props.target instanceof Room) {
             const permalinkCreator = new RoomPermalinkCreator(this.props.target);
             permalinkCreator.load();

src/components/views/dialogs/UnknownDeviceDialog.js

@@ -87,7 +87,7 @@ export default createReactClass({
         onSend: PropTypes.func.isRequired,
     },
 
-    componentWillMount: function() {
+    componentDidMount: function() {
         MatrixClientPeg.get().on("deviceVerificationChanged", this._onDeviceVerificationChanged);
     },