This fixes a few related issues in VSE code:
* 'lib_link' code was doing 'read_data' tasks (like cleaning up internal
runtime data).
* Handling of `SEQ_TYPE_SOUND_HD` deprecated type of strips was
extremely confusing (versioning done partly in 'lib_link' code, partly
in some 2.50 do_version code).
* Still using deprecated `SEQ_TYPE_SOUND_HD` strip type outside of
versioning code.
* Missing proper usage of deprecated `SEQ_TYPE_SOUND_HD` type inside of
versioning code (!).
Note that the actual conversion from `SEQ_TYPE_SOUND_HD` to
`SEQ_TYPE_SOUND_RAM` is now done in the 'after setup' versioning
process, where it is somewhat safer to add IDs. This implies that
`SEQ_TYPE_SOUND_HD` must be taken into account throughout the whole
regular versioning process (before and after liblink).
Conversion logic itself has been moved to the VSE code.
Pull Request: https://projects.blender.org/blender/blender/pulls/111135
Bastien Montagne
b454fc2161