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/components/views/location/LocationShareMenu-test.tsx

@@ -422,7 +422,7 @@ describe("<LocationShareMenu />", () => {
                 QuestionDialog,
                 expect.objectContaining({
                     button: "Try again",
-                    description: "Element could not send your location. Please try again later.",
+                    description: "HealthChat could not send your location. Please try again later.",
                     title: `We couldn't send your location`,
                     cancelButton: "Cancel",
                 }),

apps/web/test/unit-tests/components/views/location/Map-test.tsx

@@ -247,7 +247,7 @@ describe("<Map />", () => {
             expect(Modal.createDialog).toHaveBeenCalledWith(ErrorDialog, {
                 title: "Could not fetch location",
                 description:
-                    "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.",
             });
         });