fix(mobile): Change read-only mode activation method to remove double click lag

[goalie2002]

Description

Changes the read-only mode activation method from double tapping the user avatar to long pressing the user avatar. This removes the short delay that would occur on the single tap action due to the double tap detection delay. Since the single tap is by far the most used action on this button, it's preferable to make the app feel responsive there by changing to long pressing for the secondary action (read-only mode).

Fixes #21585

How Has This Been Tested?

• Both long-press and single tap the user avatar in the top bar to confirm both functions still work. Also confirm that the delay on single tap is gone.
• Single tap the user avatar in the top bar to open the subsequent menu. Both long-press and single tap the avatar in this menu to confirm both the avatar picker, and the read-only toggle functions still work. Also confirm that the delay on single tap is gone.

Screenshots (if appropriate)

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if applicable
• I have no unrelated changes in the PR.
• I have confirmed that any new dependencies are strictly necessary.
• I have written tests for new code (if applicable)
• I have followed naming conventions/patterns in the surrounding code
• All code in src/services/ uses repositories implementations for database calls, filesystem operations, etc.
• All code in src/repositories/ is pretty basic/simple and does not have any immich specific logic (that belongs in src/services/)

Please describe to which degree, if any, an LLM was used in creating this pull request.

No LLM was used for this simple change.
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[alextran1502]

Can we fix the issue but keep the double-tap behavior?

[goalie2002]

I don't think so, since to distinguish between double and single tapping, there needs to be a delay on the single tap action to allow for the second tap to be registered, in case it comes. The only compromise I can think of is reducing the delay, which means the double tap would need to be faster, but I don't think that's something you can do in code, I'm pretty sure that's controlled by the OS double tap recognition threshold. But I'm open to ideas if you have any!