Ensure -I . is the first protoc argument

The first include directory affects where protoc places the
output files.  Ensure -I . is always the first protoc argument.

Bug: 70704330
Test: m checkbuild
Change-Id: I4992e4074f612409865e6e18dc8993c6f68385fd
diff --git a/android/proto.go b/android/proto.go
index 1c70656..0cf7c26 100644
--- a/android/proto.go
+++ b/android/proto.go
@@ -23,7 +23,9 @@
 // generate the source.
 
 func ProtoFlags(ctx ModuleContext, p *ProtoProperties) []string {
-	var protoFlags []string
+	// -I . must come first, it affects where protoc places the output files.
+	protoFlags := []string{"-I ."}
+
 	if len(p.Proto.Local_include_dirs) > 0 {
 		localProtoIncludeDirs := PathsForModuleSrc(ctx, p.Proto.Local_include_dirs)
 		protoFlags = append(protoFlags, JoinWithPrefix(localProtoIncludeDirs.Strings(), "-I"))
@@ -33,8 +35,6 @@
 		protoFlags = append(protoFlags, JoinWithPrefix(rootProtoIncludeDirs.Strings(), "-I"))
 	}
 
-	protoFlags = append(protoFlags, "-I .")
-
 	return protoFlags
 }