Fix app freeze when adding photos to non-spatial layer

[xkello]

Description

Adding a photo (or any linked feature) to a relation while its parent feature was still unsaved caused the app to freeze. This is the same root cause and fix pattern as the freeze fixed in #3483, which added forceActiveFocus() before creating/opening linked features elsewhere in this file that fix was never applied to the relation drawer's own "Add feature" button and list item clicks, leaving those two entry points still exposed.

Fixes: #4636

What Changed

MMFormRelationEditor.qml: call root.forceActiveFocus() before createLinkedFeature/openLinkedFeature in the relation drawer's onButtonClicked and onFeatureClicked handlers.

Behaviour

• Before: adding a child feature to an unsaved parent while a text input (e.g. the drawer's search box) still had focus/keyboard open could freeze the app.
• After: focus is cleared first, so the keyboard commits/closes before the parent save is triggered, and the freeze no longer occurs.

[github-actions]

Coverage Report for CI Build 33078312387

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Coverage: 59.112%

Details

• Patch coverage: No coverable lines changed in this PR.

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Coverage Regressions

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Coverage Stats

Relevant Lines:	15704
Covered Lines:	9283
Line Coverage:	59.11%
Coverage Strength:	97.04 hits per line

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[github-actions]

📦 Build Artifacts Ready

OS	Status	Build	Info	Workflow run
macOS Build	📬	Mergin Maps 72261 dmg	Expires: 25/11/2026	#7226
linux Build	📬	Mergin Maps 72521 x86_64	Expires: 25/11/2026	#7252
win64 Build	📬	Mergin Maps 64281 win64	Expires: 25/11/2026	#6428
Android Build	📬	Mergin Maps 853651 APK [arm64-v8a]	Expires: 25/11/2026	#8536
	📬	Mergin Maps 853651 APK [arm64-v8a]	Google Play Store	#8536
Android Build	📬	Mergin Maps 853611 APK [armeabi-v7a]	Expires: 25/11/2026	#8536
	📬	Mergin Maps 853611 APK [armeabi-v7a]	Google Play Store	#8536
iOS Build	📬		Build number: 26.08.947811	#9478