[Thread] add Thread aconfig_declaration to java_sdk_library

This commit also moves Thread flags to Connectivity/common to ease
maintenance.

Test: m framework-connectivity-t
Ignore-AOSP-First: cherry-pick of aosp/2971692
Bug: 317290555
Merged-In: I79be1b48058ce6fb08149e18cdd7a5f5b0762769
Change-Id: I8a71f4ee49cc68a9512f432e454469200f2a5058

common/FlaggedApi.bp

@@ -22,6 +22,14 @@ aconfig_declarations {
     visibility: ["//packages/modules/Connectivity:__subpackages__"],
 }
 
+aconfig_declarations {
+    name: "com.android.net.thread.flags-aconfig",
+    package: "com.android.net.thread.flags",
+    container: "system",
+    srcs: ["thread_flags.aconfig"],
+    visibility: ["//packages/modules/Connectivity:__subpackages__"],
+}
+
 aconfig_declarations {
     name: "nearby_flags",
     package: "com.android.nearby.flags",

common/OWNERS

+per-file thread_flags.aconfig = file:platform/packages/modules/Connectivity:main:/thread/OWNERS

framework-t/Android.bp

@@ -197,6 +197,7 @@ java_sdk_library {
     ],
     aconfig_declarations: [
         "com.android.net.flags-aconfig",
+        "com.android.net.thread.flags-aconfig",
         "nearby_flags",
     ],
 }