[roll] Roll fuchsia Revert "[fidl][build] Clarify what _sdk targets include"

This reverts commit 6446505841064549a9f029f66201d85de30f2a3e.

Reason for revert: The `<fidl_library>_sdk` targets should depend on
`<fidl_library>` as described in https://fxbug.dev/381123422.

Comment improvements unrelated to the main intent of the original commit
are retained.

Original change's description:
> [fidl][build] Clarify what _sdk targets include
>
> Note that the `<fidl_library>_sdk` targets do not include
> `<fidl_library>`. Also correct comments that imply that the former do
> not include compatibility testing.
>
> Original-Bug: 366221510
> Change-Id: I1f7f309464c3bff9deda61f79d3ed282d7a1d1e3
> Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1143478
> Reviewed-by: Ian McKellar <ianloic@google.com>
> Commit-Queue: David Dorwin <ddorwin@google.com>

Original-Bug: 381123422, 366221510
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1164113
Original-Revision: b998bc4a9a17fab5f9d2d598a354837b8c4bc80e
GitOrigin-RevId: 642cd9cb060c333dd5d548809754a2cb9524ac34
Change-Id: I8236a8a5d9ffa0f974716bee7ac60271047d8171
diff --git a/stem b/stem
index ac7cfd6..f918fbc 100644
--- a/stem
+++ b/stem
@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="2102da12b8d9b244f4b6a8bab7c21cf696b7b6af"/>
+             revision="b998bc4a9a17fab5f9d2d598a354837b8c4bc80e"/>
   </projects>
   <hooks>
     <hook name="install-environment"