Change visibility of media/learning/common.

Visibility of media/learning/common:interfaces will need to include
new generated targets for the MojoLPM fuzzer.

See https://chromium-review.googlesource.com/c/chromium/src/+/2115512.

Since there shouldn't be anything other than generated targets under
media/learning/mojo/public/mojom, adding a blanket whitelist.

Change-Id: I64f2aca281fed37e4ecfdfcf901a73860e85c9e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2120413
Commit-Queue: Chrome Cunningham <chcunningham@chromium.org>
Auto-Submit: Mark Brand <markbrand@google.com>
Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753448}

media/learning/common/BUILD.gn

@@ -9,8 +9,7 @@ component("common") {
     "//media/learning/impl:*",
     "//media/learning/impl:test_support",
     "//media/learning/mojo/public/cpp:*",
-    "//media/learning/mojo/public/mojom:mojom",
-    "//media/learning/mojo/public/mojom:mojom_blink",
+    "//media/learning/mojo/public/mojom:*",
     "//media/learning/mojo:*",
     "//media/learning/common:unit_tests",