Remove dependency on libolm (#12704)

* Remove dependency on libolm

We no longer use this (and haven't for some time, afaict).

* Make olm a dev dep

* Revert "Make olm a dev dep"

This reverts commit f733cdfaf0d7af198b89a10021a976e8f4fff632.

package.json

@@ -73,7 +73,6 @@
         "@matrix-org/analytics-events": "^0.23.0",
         "@matrix-org/emojibase-bindings": "^1.1.2",
         "@matrix-org/matrix-wysiwyg": "2.37.4",
-        "@matrix-org/olm": "3.2.15",
         "@matrix-org/react-sdk-module-api": "^2.4.0",
         "@matrix-org/spec": "^1.7.0",
         "@sentry/browser": "^8.0.0",