test: rebrand hardcoded 'Element' test expectations to 'HealthChat'

Update brand-string assertions and snapshots that asserted the upstream
'Element' brand to the HealthChat brand:
- positionFailureMessage, Map, LocationShareMenu (geolocation messages)
- SupportedBrowser, init (incompatible-browser title + snapshot)
- ElectronPlatform (device display name 'HealthChat Desktop: <os>')
- RoomView (third-party invite waiting view)
- MatrixChat soft-logout snapshot

Leaves non-brand failures untouched (e.g. MatrixChat multi-tab lockout,
extended-profile mock gaps).

apps/web/test/unit-tests/utils/location/positionFailureMessage-test.ts

@@ -18,7 +18,7 @@ describe("positionFailureMessage()", () => {
     it.each<TestCase>([
         [
             1,
-            "Element was denied permission to fetch your location. Please allow location access in your browser settings.",
+            "HealthChat was denied permission to fetch your location. Please allow location access in your browser settings.",
         ],
         [2, "Failed to fetch your location. Please try again later."],
         [3, "Timed out trying to fetch your location. Please try again later."],