Reformat GN files.

`gn format` recently [1] changed its formatting behavior
for deps, source, and a few other elements when they
are assigned (with =) single-element lists to be consistent
with the formatting of updates (with +=) with single-element.

Now that we've rolled in a GN binary with the change,
reformat all files so that people don't get presubmit
warnings due to this.

CL generated with:
$ git ls-files | grep BUILD.gn | xargs gn format
$ gn format build_overrides/build.gni
$ gn format build_overrides/gtest.gni
$ gn format modules/audio_coding/audio_coding.gni
$ gn format webrtc.gni
$ gn format .gn

Plus a few manual changes to add exceptions for
"public_deps" (after changing these lines the presubmit
started to complain).

[1] - https://gn-review.googlesource.com/c/gn/+/6860

Bug: webrtc:11302
Change-Id: Iac29d23c1618ebef925c972e2891cd9f4e8cd613
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/166882
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30334}

resources/audio_processing/test/py_quality_assessment/BUILD.gn

@@ -11,9 +11,7 @@ import("../../../../webrtc.gni")
 if (rtc_include_tests) {
   copy("noise_tracks") {
     testonly = true
-    sources = [
-      "noise_tracks/city.wav",
-    ]
+    sources = [ "noise_tracks/city.wav" ]
     outputs = [
       "$root_build_dir/py_quality_assessment/noise_tracks/{{source_file_part}}",
     ]
@@ -21,11 +19,7 @@ if (rtc_include_tests) {
 
   copy("probing_signals") {
     testonly = true
-    sources = [
-      "probing_signals/tone-880.wav",
-    ]
-    outputs = [
-      "$root_build_dir/py_quality_assessment/probing_signals/{{source_file_part}}",
-    ]
+    sources = [ "probing_signals/tone-880.wav" ]
+    outputs = [ "$root_build_dir/py_quality_assessment/probing_signals/{{source_file_part}}" ]
   }  # probing_signals
 }