Fix weight tying in TF-ESM
TF ESM cloned weights instead of tying, which worked when loading from PT but broke when loading from safetensors. This resolves the issue by correctly tying weights when this is enabled in the config. Fixes an ongoing CI error raised by @ydshieh 
Also cc @gante in case he hates how I handled weight tying here, I don't want to break TF convention too much!<|||||>_The documentation is not available anymore as the PR was closed or merged._<|||||>@Rocketknight1 I'm cool with this :D 