[gn] Deduplicate grd inputs in generate_devtools_grd action

Deduplicate the iteration over `_expected_grd_files` in the
`generate_devtools_grd` action inputs by hoisting it outside the
`is_debug` condition.

Bug: None
Change-Id: I5b2c07d1f77e4715666e84929743d63df23e8650
TAG=agy
CONV=edc30b47-127d-42af-90d9-8a14eb4093c6
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/8278420
Reviewed-by: Alex Rudenko <alexrudenko@chromium.org>
Auto-Submit: Simon Zünd <szuend@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>

Author: szuend

BUILD.gn

@@ -168,17 +168,14 @@ action("generate_devtools_grd") {
   ]
 
   inputs = []
+  foreach(_grd_file, _expected_grd_files) {
+    inputs += [ "$target_gen_dir/$_grd_file" ]
+  }
 
   if (is_debug) {
     deps = [ ":devtools_frontend_resources" ]
-    foreach(_grd_file, _expected_grd_files) {
-      inputs += [ "$target_gen_dir/$_grd_file" ]
-    }
   } else {
     deps = [ ":compress" ]
-    foreach(_grd_file, _expected_grd_files) {
-      inputs += [ "$target_gen_dir/$_grd_file" ]
-    }
     foreach(_grd_file, _compressable_grd_files) {
       inputs += [ "$target_gen_dir/$_grd_file.compressed" ]
     }