Make `controllee_map_` has the client UUID.

In the previous CL (crrev.com/c/5740637), `AddControllee()` returns
soon after the initial CHECKs in the function ends.  However, it made
the `uuid` not recorded to `controllee_map_`.

When the `ServiceWorkerVersion::Uncontrol()` is called, it fails with
CHECK because the `uuid` is not registered to anywhere.

Bug: 357954498
Change-Id: I24c7736c708ccbf0ce6d40692325b161f70caa70
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5768275
Reviewed-by: Minoru Chikamune <chikamune@chromium.org>
Reviewed-by: Keita Suzuki <suzukikeita@chromium.org>
Reviewed-by: Shunya Shishido <sisidovski@chromium.org>
Commit-Queue: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1338798}