Fix null outfit gallery observer pointer

[Geenz]

Fixes a null pointer crash in the outfit gallery I managed to hit on macOS working on some stuff.

[Copilot]

Pull Request Overview

This PR ensures the mOutfitsObserver member is initialized before any use in updateAddedCategory, preventing a null-pointer crash.

• Moved observer initialization to the start of updateAddedCategory.
• Removed the duplicate observer creation block later in the method.

[akleshchev]

Why does this use mOutfitsObserver isntead of inherited mCategoriesObserver?

[Geenz]

@akleshchev Not sure - sounds like a good opportunity to consolidate though.

[Copilot]

Pull Request Overview

This PR replaces a dedicated mOutfitsObserver with the shared mCategoriesObserver to prevent null-pointer crashes in the outfit gallery and removes redundant observer management code.

• Deleted mOutfitsObserver member and its init/cleanup
• Updated all addCategory/removeCategory calls to use mCategoriesObserver

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
indra/newview/lloutfitgallery.h	Removed mOutfitsObserver declaration
indra/newview/lloutfitgallery.cpp	Deleted init/remove of old observer and switched calls to mCategoriesObserver

Comments suppressed due to low confidence (2)

indra/newview/lloutfitgallery.cpp:729

• The destructor no longer unregisters or deletes mCategoriesObserver. Verify that cleanup is handled in the base class or reintroduce proper removal to avoid dangling observers or memory leaks.

LLOutfitGallery::~LLOutfitGallery()

indra/newview/lloutfitgallery.cpp:793

• Ensure that mCategoriesObserver is initialized and registered with gInventory before use; otherwise these calls may still dereference a null pointer.

mCategoriesObserver->addCategory(cat_id, [this, outfits]()

[Geenz]

@akleshchev @maxim-productengine Go ahead and give this a re-review. From my testing, there doesn't seem to be any issues.