Fully initialize global state in tests by calling apply_options

As stated in this comment: #1926 (comment)
A global state is not fully initialized without `apply_options` being called,
which the current `with_server` test helper does not do.

This means that when tests are being run, detections around things like
test library are not performed, which can yield unexpected results to
developers, especially addon authors.

This commit changes the `with_server` test helper to call `apply_options`.

lib/ruby_lsp/test_helper.rb

@@ -21,6 +21,7 @@ def with_server(source = nil, uri = Kernel.URI("file:///fake.rb"), stub_no_typec
       &block)
       server = RubyLsp::Server.new(test_mode: true)
       server.global_state.stubs(:typechecker).returns(false) if stub_no_typechecker
+      server.global_state.apply_options({})
 
       if source
         server.process_message({