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}

tools_webrtc/presubmit_checks_lib/testdata/circular_dependency/BUILD.gn

@@ -2,13 +2,9 @@ toolchain("toolchain") {
 }
 
 static_library("foo") {
-  deps = [
-    ":bar",
-  ]
+  deps = [ ":bar" ]
 }
 
 static_library("bar") {
-  deps = [
-    ":foo",
-  ]
+  deps = [ ":foo" ]
 }

tools_webrtc/presubmit_checks_lib/testdata/common_prefix/BUILD.gn

@@ -11,7 +11,5 @@ rtc_library("webrtc") {
     "call.h",
     "dummy_source.h",
   ]
-  deps = [
-    "call",
-  ]
+  deps = [ "call" ]
 }

tools_webrtc/presubmit_checks_lib/testdata/dangerous_filename/BUILD.gn

@@ -9,7 +9,5 @@
 # "libc++" is considered a "dangerous filename" because it's an invalid regex.
 
 target("dummy_target") {
-  sources = [
-    "libc++/dummy_subpackage_file.h",
-  ]
+  sources = [ "libc++/dummy_subpackage_file.h" ]
 }

tools_webrtc/presubmit_checks_lib/testdata/dangerous_filename/libc++/BUILD.gn

@@ -7,7 +7,5 @@
 # be found in the AUTHORS file in the root of the source tree.
 
 group("dummy_subpackage") {
-  sources = [
-    "dummy_subpackage.h",
-  ]
+  sources = [ "dummy_subpackage.h" ]
 }

tools_webrtc/presubmit_checks_lib/testdata/no_errors/BUILD.gn

@@ -7,16 +7,10 @@
 # be found in the AUTHORS file in the root of the source tree.
 
 group("testdata") {
-  deps = [
-    ":dummy_target",
-  ]
+  deps = [ ":dummy_target" ]
 }
 
 static_library("dummy_target") {
-  sources = [
-    "dummy.cc",
-  ]
-  deps = [
-    "subdir",
-  ]
+  sources = [ "dummy.cc" ]
+  deps = [ "subdir" ]
 }