pm: Require manifest.json for .dm (dex-metadata) files.

Example file:
  $> unzip CtsApkVerityTestAppPrebuilt.dm manifest.json ; cat manifest.json
  {
    "packageName": "android.appsecurity.cts.apkveritytestapp",
    "versionCode": 30
  }

Test: adb install-multiple -r foo.apk foo.dm
Test: atest FrameworksServicesTests:com.android.server.pm.dex.DexMetadataHelperTest
Bug: 179295368
Change-Id: I7a3c442bb27da5948bc9ead146c77213de6b56cc