Broaden support for matrix spec versions (#12154)

Something of a compainion to
https://github.com/matrix-org/matrix-js-sdk/pull/4014, but also covering the
issues discussed at
https://github.com/matrix-org/matrix-js-sdk/issues/3915#issuecomment-1865221366.

In short: we should not reject servers which only implement recent versions of
the spec. Doing so holds back the ecosystem by requiring all new servers to
implement features that nobody actually uses any more.

test/Lifecycle-test.ts

@@ -453,10 +453,7 @@ describe("Lifecycle", () => {
 
             it("should show a toast if the matrix server version is unsupported", async () => {
                 const toastSpy = jest.spyOn(ToastStore.sharedInstance(), "addOrReplaceToast");
-                mockClient.getVersions.mockResolvedValue({
-                    versions: ["r0.6.0"],
-                    unstable_features: {},
-                });
+                mockClient.isVersionSupported.mockImplementation(async (version) => version == "r0.6.0");
                 initLocalStorageMock({ ...localStorageSession });
 
                 expect(await restoreFromLocalStorage()).toEqual(true);