ydbd crashes on `BACKUP my_collection` if path is not present

[s-sabitova]

Steps to reproduce:

CREATE BACKUP COLLECTION `my_collection`
    ( TABLE `/Root/database/path/that/doesnt/exist`)
WITH ( STORAGE = 'cluster', INCREMENTAL_BACKUP_ENABLED = 'true' );

BACKUP `my_collection`;

Actual result:

The node where SchemeShard is crashes. Log is filled with the following errors:

Expected result:

1. CREATE BACKUP COLLECTION results with an error "Cannot find path" in the first place
2. ydbd doesn't crash

[Enjection]

Probably fixed here #26201

[s-sabitova]

fixed

[CyberROFL]

@Enjection нужно портировать/привязать pr-ы.