Define aconfig flags for settingslib

Adds a settingslib.aconfig that is separate from the existing
settlingslib_media_flag_declarations.aconfig file. The existing aconfig
uses a media package and it seemed to make more sense to break out a
shared settlingslib flag file

The new file defines com.settingslib.flags.new_status_bar_icons

Test: compile
Test: settingslib robo tests, settingslib unit tests
Bug: 314812750
Flag: ACONFIG com.settingslib.flags.new_status_bar_icons DEVELOPMENT
Change-Id: I33399555c81acaed314e2b8dc2fed37ef7249050
diff --git a/packages/SettingsLib/tests/robotests/Android.bp b/packages/SettingsLib/tests/robotests/Android.bp
index 732c336..f4ddd0a 100644
--- a/packages/SettingsLib/tests/robotests/Android.bp
+++ b/packages/SettingsLib/tests/robotests/Android.bp
@@ -50,7 +50,7 @@
         "androidx.test.core",
         "androidx.core_core",
         "flag-junit",
-        "settingslib_flags_lib",
+        "settingslib_media_flags_lib",
         "testng", // TODO: remove once JUnit on Android provides assertThrows
     ],
     java_resource_dirs: ["config"],