fix: blank_common.yaml added back to support library_v1 problems

[marslanabdulrauf]

Related ticket

https://github.com/mitodl/hq/issues/9962 (MIT Internal)

Description

Legacy Problem Editor was removed under #37795 however its still being used in legacy library or library v1 which causes issues and does not show problem option while adding a new component.

This PR just adds blank_common.yaml file back into xmodule > templates > problem templates to keep library_v1 working as expected for problems

Useful information to include:

We can entirely remove it under #37931

Testing instructions

1. Make sure the setup is running fine on master branch
2. Add new library(legacy)
3. you should see Problem option as well while adding a new component

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