Add connection pool that doesn't keep failed sockets

[planarvoid]

Fixes #9843
There seems to be a known issue in OkHttp with Http2. Whenever there is a SockedTimeoutException, the socked that failed is kept in the pool and this causes the same exception to happen again even though the connection is restored. This solution should fix the issue by setting the connection pool to not hold failed sockets.
It's based on this answer: square/okhttp#3146 (comment)

To test:

• Upload a cropped gravatar
• Everything works as expected

Update release notes:

• If there are user facing changes, I have added an item to RELEASE-NOTES.txt.

[loremattei]

Hey! I'm moving this to 12.6 since 12.5 has been cut. If you want this to land 12.5, please feel free to target the release branch and ping me to build a new beta.

[malinajirka]

Thanks for looking into this @planarvoid !

I've tested both successful upload and re-upload after timed out upload and everything works as expected. Thanks!