[Web] Fix issue where focus timer would throw continuously

[adamscott]

Two commits.

1. The first makes Web IME code return early instead of being inside an all-encompassing if statement.
2. The second fixes [Web] Editor throws continuously when calling internally GodotIME.ime.focus() #98928

[bruvzg]

Seems to be working fine (tested IME on macOS and Windows with Firefox and Chromium).

[Repiteo]

Thanks!