fix: bob codegen deletes view specs when codegen type is all

[atlj]

Summary

Fixes #728

The codegen patcher script was deleting the whole facebook namespace when the codegen type was all or module. This was not a problem when the type was module but when the type was all, view manager specs were also getting removed.s

Test plan

1. Create a new turbo module
2. Set codegen type to all
3. Add turbo module specs
4. Run yarn bob build --target codegen
5. Make sure android/generated/java/com/facebook/react exists and has view manager specs

[sidorchukandrew]

Thank you for fixing this!!