Export shared member name comparator and use it in team chat sharing

[Saby-Bishops]

Motivation

• Provide a stable, standalone name-based comparator so other modules can apply the same team-member sorting semantics when userDoc is missing or partial.
• Prevent divergent comparator behavior across modules by centralizing the sort key and making it explicitly consumable.

Description

• Exported a resilient sort key and comparator in src/app/teams/teams.utils.ts as memberSortName and memberNameCompare with a brief docstring describing intended external usage.
• Hardened the comparator fallback chain to use userDoc.doc.lastName, userDoc.lastName, userDoc.fullName, name, and finally userId when available.
• Added an explicit external consumer by importing and applying memberNameCompare in src/app/shared/dialogs/dialogs-chat-share.component.ts to sort membership recipients before sending notifications.
• Added unit tests in src/app/shared/dialogs/dialogs-chat-share.component.spec.ts that assert membership filtering and stable name sorting when userDoc is missing.

Testing

• Added a unit spec file src/app/shared/dialogs/dialogs-chat-share.component.spec.ts covering membership filtering and name-sorting behavior (tests present in the tree).
• Attempted to run the spec with npm run test / npx ng test for the single spec, but automated test execution failed in this environment due to missing Angular CLI (ng: not found / CLI executable unavailable).
• No other automated test failures detected in this change set during local validation steps.

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Codex Task