Cleanup BUILD.gn files from imports like foo:foo

Repalce all occurrences of foo:foo in deps with just foo in BUILD.gn
files.

Done with Sublime regex replace.
Find: \b([-a-zA-Z0-9_]+):+\1\b
In: *.gn
Replace with: \1

Bug: None
Change-Id: I40aba1b14face687a595b852ffe443cb20197611
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/127899
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27225}

modules/congestion_controller/goog_cc/BUILD.gn

@@ -205,7 +205,7 @@ if (rtc_include_tests) {
       "../../../api/units:timestamp",
       "../../../logging:rtc_event_log_api",
       "../../../rtc_base:checks",
-      "../../remote_bitrate_estimator:remote_bitrate_estimator",
+      "../../remote_bitrate_estimator",
       "//third_party/abseil-cpp/absl/types:optional",
     ]
   }