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/SupportedBrowser-test.ts

@@ -102,7 +102,7 @@ describe("SupportedBrowser", () => {
         expect(toastSpy).toHaveBeenCalledWith(
             expect.objectContaining({
                 component: GenericToast,
-                title: "Element does not support this browser",
+                title: "HealthChat does not support this browser",
             }),
         );