Description of problem:
Incremental syncable content export of a file repo always export full content of the repository.

Version-Release number of selected component (if applicable):
6.13.0 snap 11

How reproducible:
always

Steps to Reproduce:
1) Create a file repo, sync it.
2) Export complete: hammer content-export complete library --format syncable --organization-id 1
3) Check the export path.
4) Upload one file into the repo.
5) Export incremental: hammer content-export incremental library --format syncable --organization-id 1
6) Check the export path.

Actual results:

3)
[root@sat ~]# ll /var/lib/pulp/exports/Default_Organization/Export-Library-SYNCABLE/1.0/2023-02-21T10-24-55-05-00/custom/Files/X/
total 16
rw-rr-. 3 pulp pulp 1024 Feb 21 10:01 1.iso
rw-rr-. 3 pulp pulp 1024 Feb 21 10:01 2.iso
rw-rr-. 3 pulp pulp 1024 Feb 21 10:01 3.iso
rw-rr-. 2 pulp pulp 228 Feb 21 10:01 PULP_MANIFEST

6)
[root@sat ~]# ll /var/lib/pulp/exports/Default_Organization/Export-Library-SYNCABLE/2.0/2023-02-21T10-30-45-05-00/custom/Files/X/
total 20
rw-rr-. 3 pulp pulp 1024 Feb 21 10:01 1.iso
rw-rr-. 3 pulp pulp 1024 Feb 21 10:01 2.iso
rw-rr-. 3 pulp pulp 1024 Feb 21 10:01 3.iso
rw-rr-. 2 pulp pulp 1024 Feb 21 10:27 7.iso
rw-rr-. 2 pulp pulp 304 Feb 21 10:27 PULP_MANIFEST

Expected results:
1.iso, 2.iso, 3.iso should be missing in the incremental export.

Additional information:
Same behaviour seen for 'repository' and 'version' syncable exports.