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}

api/audio_codecs/g722/BUILD.gn

@@ -14,9 +14,7 @@ if (is_android) {
 
 rtc_source_set("audio_encoder_g722_config") {
   visibility = [ "*" ]
-  sources = [
-    "audio_encoder_g722_config.h",
-  ]
+  sources = [ "audio_encoder_g722_config.h" ]
 }
 
 rtc_library("audio_encoder_g722") {

api/audio_codecs/ilbc/BUILD.gn

@@ -14,9 +14,7 @@ if (is_android) {
 
 rtc_source_set("audio_encoder_ilbc_config") {
   visibility = [ "*" ]
-  sources = [
-    "audio_encoder_ilbc_config.h",
-  ]
+  sources = [ "audio_encoder_ilbc_config.h" ]
 }
 
 rtc_library("audio_encoder_ilbc") {

api/audio_codecs/isac/BUILD.gn

@@ -20,36 +20,24 @@ if (is_android) {
 rtc_source_set("audio_encoder_isac") {
   visibility = [ "*" ]
   poisonous = [ "audio_codecs" ]
-  public = [
-    "audio_encoder_isac.h",
-  ]
+  public = [ "audio_encoder_isac.h" ]
   public_configs = [ ":isac_config" ]
   if (current_cpu == "arm") {
-    deps = [
-      ":audio_encoder_isac_fix",
-    ]
+    deps = [ ":audio_encoder_isac_fix" ]
   } else {
-    deps = [
-      ":audio_encoder_isac_float",
-    ]
+    deps = [ ":audio_encoder_isac_float" ]
   }
 }
 
 rtc_source_set("audio_decoder_isac") {
   visibility = [ "*" ]
   poisonous = [ "audio_codecs" ]
-  public = [
-    "audio_decoder_isac.h",
-  ]
+  public = [ "audio_decoder_isac.h" ]
   public_configs = [ ":isac_config" ]
   if (current_cpu == "arm") {
-    deps = [
-      ":audio_decoder_isac_fix",
-    ]
+    deps = [ ":audio_decoder_isac_fix" ]
   } else {
-    deps = [
-      ":audio_decoder_isac_float",
-    ]
+    deps = [ ":audio_decoder_isac_float" ]
   }
 }
 

api/audio_codecs/opus/BUILD.gn

@@ -35,20 +35,14 @@ rtc_library("audio_encoder_opus_config") {
 
 rtc_source_set("audio_decoder_opus_config") {
   visibility = [ "*" ]
-  sources = [
-    "audio_decoder_multi_channel_opus_config.h",
-  ]
+  sources = [ "audio_decoder_multi_channel_opus_config.h" ]
 }
 
 rtc_library("audio_encoder_opus") {
   visibility = [ "*" ]
   poisonous = [ "audio_codecs" ]
-  public = [
-    "audio_encoder_opus.h",
-  ]
-  sources = [
-    "audio_encoder_opus.cc",
-  ]
+  public = [ "audio_encoder_opus.h" ]
+  sources = [ "audio_encoder_opus.cc" ]
   deps = [
     ":audio_encoder_opus_config",
     "..:audio_codecs_api",
@@ -80,12 +74,8 @@ rtc_library("audio_decoder_opus") {
 rtc_library("audio_encoder_multiopus") {
   visibility = [ "*" ]
   poisonous = [ "audio_codecs" ]
-  public = [
-    "audio_encoder_multi_channel_opus.h",
-  ]
-  sources = [
-    "audio_encoder_multi_channel_opus.cc",
-  ]
+  public = [ "audio_encoder_multi_channel_opus.h" ]
+  sources = [ "audio_encoder_multi_channel_opus.cc" ]
   deps = [
     "..:audio_codecs_api",
     "../../../modules/audio_coding:webrtc_multiopus",