[RESTRICT AUTOMERGE][pm] still allow debuggable for system app downgrades

Turns out we do have internal tests that downgrades system apps, so adding this exception to allow for that.

BUG: 267232653
BUG: 256202273

Test: manual
Change-Id: Ie281bbdc8788ee64ff99a7c5150da7ce7926235e
(cherry picked from commit ceeca68b8c3f0ed8427b0212f63defe2f075146e)
(cherry picked from commit on googleplex-android-review.googlesource.com host: 3a04799f68de6b77fc89faddda032b1031551e78)
Merged-In: Ie281bbdc8788ee64ff99a7c5150da7ce7926235e

services/core/java/com/android/server/pm/InstallPackageHelper.java

diff --git a/services/core/java/com/android/server/pm/InstallPackageHelper.java b/services/core/java/com/android/server/pm/InstallPackageHelper.java
index ae62f41..c32a57c 100644
--- a/services/core/java/com/android/server/pm/InstallPackageHelper.java
+++ b/services/core/java/com/android/server/pm/InstallPackageHelper.java
@@ -2477,15 +2477,19 @@
                     if (disabledPs != null) {
                         dataOwnerPkg = disabledPs.getPkg();
                     }
-                    try {
-                        PackageManagerServiceUtils.checkDowngrade(dataOwnerPkg, pkgLite);
-                    } catch (PackageManagerException e) {
-                        String errorMsg = "System app: " + packageName + " cannot be downgraded to"
-                                + " older than its preloaded version on the system image. "
-                                + e.getMessage();
-                        Slog.w(TAG, errorMsg);
-                        return Pair.create(
-                                PackageManager.INSTALL_FAILED_VERSION_DOWNGRADE, errorMsg);
+                    if (!Build.IS_DEBUGGABLE && !dataOwnerPkg.isDebuggable()) {
+                        // Only restrict non-debuggable builds and non-debuggable version of the app
+                        try {
+                            PackageManagerServiceUtils.checkDowngrade(dataOwnerPkg, pkgLite);
+                        } catch (PackageManagerException e) {
+                            String errorMsg =
+                                    "System app: " + packageName + " cannot be downgraded to"
+                                            + " older than its preloaded version on the system"
+                                            + " image. " + e.getMessage();
+                            Slog.w(TAG, errorMsg);
+                            return Pair.create(
+                                    PackageManager.INSTALL_FAILED_VERSION_DOWNGRADE, errorMsg);
+                        }
                     }
                 }
             }