Update rich text editor dependency and associated changes (#11098)

* fix logic error

* update types

* extract message content to variable

* use the new messageContent property

* sort out mention types to make them a  map

* update getMentionAttributes to use AllowedMentionAttributes

* add plain text handling

* change type and handling for attributes when creating a mention in plain text

* tidy, add comment

* revert TS config change

* fix broken types in test

* update tests

* bump rte

* fix import and ts errors

* fix broken tests

package.json

@@ -61,7 +61,7 @@
     "dependencies": {
         "@babel/runtime": "^7.12.5",
         "@matrix-org/analytics-events": "^0.5.0",
-        "@matrix-org/matrix-wysiwyg": "^2.2.2",
+        "@matrix-org/matrix-wysiwyg": "^2.3.0",
         "@matrix-org/react-sdk-module-api": "^0.0.5",
         "@sentry/browser": "^7.0.0",
         "@sentry/tracing": "^7.0.0",