pane: Turn off preview mode when pinning a tab (#22501)

I opened the tab in preview mode, pinned it, then I opened another file,
but its tab unexpectedly closed.


https://github.com/user-attachments/assets/b857382e-f0ad-4d5a-9036-19de01663c97

Pinning a tab now turns off preview mode.



https://github.com/user-attachments/assets/e34b7c7f-452b-4f36-99c1-e0c68429225c


Release Notes:

- Pinning a preview tab will now turn off preview mode

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Signed-off-by: Hayashi Mikihiro <34ttrweoewiwe28@gmail.com>
Co-authored-by: Bennet Bo Fenner <bennet@zed.dev>