Revert "Only allow setting presigned without preprocessed on targetSdk < 30"

This reverts commit 6158528e15.

Reason for revert: DroidMonitor-triggered revert due to breakage https://android-build.corp.google.com/builds/quarterdeck?branch=git_udc-d1-dev-plus-aosp&target=aosp_bramble-trunk_staging-userdebug&lkgb=10771573&lkbb=10771600&fkbb=10771587, bug https://buganizer.corp.google.com/issues/299369971

BUG: 299369971

Change-Id: I6bf6eb5c0fb9e30197e145121adc7ed58871526f

scripts/check_target_sdk_less_than_30.py

@@ -1,30 +0,0 @@
-#!/usr/bin/env python3
-
-import subprocess
-import argparse
-import re
-import sys
-
-def main():
-    parser = argparse.ArgumentParser()
-    parser.add_argument('aapt2', help = "the path to the aapt2 executable")
-    parser.add_argument('apk', help = "the apk to check")
-    parser.add_argument('stampfile', help = "a file to touch if successful")
-    args = parser.parse_args()
-
-    regex = re.compile(r"targetSdkVersion: *'([0-9]+)'")
-    output = subprocess.check_output([args.aapt2, "dump", "badging", args.apk], text=True)
-    targetSdkVersion = None
-    for line in output.splitlines():
-        match = regex.fullmatch(line.strip())
-        if match:
-            targetSdkVersion = int(match.group(1))
-            break
-
-    if targetSdkVersion is None or targetSdkVersion >= 30:
-        sys.exit(args.apk + ": Prebuilt, presigned apks with targetSdkVersion >= 30 (or a codename targetSdkVersion) must set preprocessed: true in the Android.bp definition (because they must be signed with signature v2, and the build system would wreck that signature otherwise)")
-
-    subprocess.check_call(["touch", args.stampfile])
-
-if __name__ == "__main__":
-    main()