Fix Plex startup race condition

[jjlawren]

Description:

When starting up, there was a potential race condition where we would attempt to create new media_player entities before the listening dispatcher was set up. This delays the connection of the websocket connection until HA is fully started. This ensures the dispatch listener for new media_player entities is available when new Plex clients are found during the initial scan.

Related issues: fixes #28928 fixes #28491
Possibly a fix for #28485

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

[jimmyeao]

Now all of my plex media players show as unavailable?

[jjlawren]

@jimmyeao this is a merged PR that has not been released yet. Please open an issue if you're encountering a new problem.

[jimmyeao]

Ah, now I feel stupid! How would i go about testing this?

[jjlawren]

It'll be in 0.102.1 which should be released shortly.