Add workaround for handling versionMajor with string type

A bug in bundletool sets versionMajor as string instead of int. Until
it's fixed, we need to workaround it.

Bug: 379219371
Test: manully installed an apk that has versionMajor set to string
FLAG: android.content.pm.sdk_dependency_installer
Change-Id: Ie2a9809b49b4c7cd9136d610e98e6bd15a660ce6