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/settings/ChangeAvatar.js

@@ -55,7 +55,7 @@ export default createReactClass({
         };
     },
 
-    componentWillMount: function() {
+    componentDidMount: function() {
         MatrixClientPeg.get().on("RoomState.events", this.onRoomStateEvents);
     },
 

src/components/views/settings/ChangePassword.js

@@ -78,7 +78,7 @@ export default createReactClass({
         };
     },
 
-    componentWillMount: function() {
+    componentDidMount: function() {
         this._sessionStore = sessionStore;
         this._sessionStoreToken = this._sessionStore.addListener(
             this._setStateFromSessionStore,

src/components/views/settings/EventIndexPanel.js

@@ -63,7 +63,7 @@ export default class EventIndexPanel extends React.Component {
         }
     }
 
-    async componentWillMount(): void {
+    async componentDidMount(): void {
         this.updateState();
     }
 

src/components/views/settings/KeyBackupPanel.js

@@ -38,7 +38,7 @@ export default class KeyBackupPanel extends React.PureComponent {
         };
     }
 
-    componentWillMount() {
+    componentDidMount() {
         this._checkKeyBackupStatus();
 
         MatrixClientPeg.get().on('crypto.keyBackupStatus', this._onKeyBackupStatus);

src/components/views/settings/Notifications.js

@@ -87,7 +87,7 @@ export default createReactClass({
         };
     },
 
-    componentWillMount: function() {
+    componentDidMount: function() {
         this._refreshFromServer();
     },
 

src/components/views/settings/tabs/user/HelpUserSettingsTab.js

@@ -40,7 +40,7 @@ export default class HelpUserSettingsTab extends React.Component {
         };
     }
 
-    componentWillMount(): void {
+    componentDidMount(): void {
         PlatformPeg.get().getAppVersion().then((ver) => this.setState({vectorVersion: ver})).catch((e) => {
             console.error("Error getting vector version: ", e);
         });

src/components/views/settings/tabs/user/PreferencesUserSettingsTab.js

@@ -81,7 +81,7 @@ export default class PreferencesUserSettingsTab extends React.Component {
         };
     }
 
-    async componentWillMount(): void {
+    async componentDidMount(): void {
         const platform = PlatformPeg.get();
 
         const autoLaunchSupported = await platform.supportsAutoLaunch();