Do not disable adb_keys module type

The module can be added as a dependency, in which the reverse dependency
will fail with "depending on a disabled module" error. Given that the
module is setting `Disabled()` in `GenerateBuildActions()`, the reverse
dependencies does not have the information about whether the module will
be disabled or not in DepsMutator.

Test: m nothing
Bug: 371107666
Change-Id: I6a0a03a1e777bfb2655a55671696a54453b3475e
diff --git a/etc/adb_keys.go b/etc/adb_keys.go
index 1bce2f1..a2df41c 100644
--- a/etc/adb_keys.go
+++ b/etc/adb_keys.go
@@ -37,7 +37,6 @@
 func (m *AdbKeysModule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	productVariables := ctx.Config().ProductVariables()
 	if !(android.Bool(productVariables.Debuggable) && len(android.String(productVariables.AdbKeys)) > 0) {
-		m.Disable()
 		m.SkipInstall()
 		return
 	}