fix: extended details overlay position in slideshow

[Neer-rn]

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Fixed an issue where the "Extended Details" overlay (e.g., File Name) would shift upwards during a slideshow.
• The bottom_actions_dummy view, which reserves space for bottom actions, was incorrectly remaining visible when new fragments were created during a fullscreen slideshow.
• Added a check in PhotoFragment.onCreateView to immediately hide this dummy view if the fragment is initialized in fullscreen mode.

Tests performed

• Manually tested on my android device.
• Enabled "Show extended details" -> "File name only" in Settings.
• Started a slideshow and verified that the file name text remains pinned to the bottom edge for the first, second, and subsequent images.
• Verified that toggling fullscreen manually (tapping the screen) still correctly shows/hides the bottom actions and overlay.

Before & after preview

Before: The text overlay would jump up and float over the image after the first slide.
After: The text overlay stays consistently at the bottom of the screen for all slides.

Closes the following issue(s)

• Closes misplacement of extended information during slideshow #800

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• I have self-reviewed my pull request (no typos, formatting errors, etc.).
• All checks are passing.

[naveensingh]

Looks good, thanks.