Opt the CredMan app in to R8 full mode for trimming optimization.

Bug: 253327460
Test: build
Change-Id: I5589d11356cff8844d8721c9a09de210a79d38c5
diff --git a/packages/CredentialManager/Android.bp b/packages/CredentialManager/Android.bp
index 51943ff..25529bb 100644
--- a/packages/CredentialManager/Android.bp
+++ b/packages/CredentialManager/Android.bp
@@ -32,4 +32,8 @@
     platform_apis: true,
 
     kotlincflags: ["-Xjvm-default=enable"],
+
+    optimize: {
+        proguard_compatibility: false,
+    },
 }