Description of problem:
Stratisd 3.4.0 unconditionally requires a "pool_name" key in the LUKS token on an encrypted device, but the "pool_name" key is not present when the encrypted device was initialized by an earlier version of stratisd.

Version-Release number of selected component (if applicable):
stratisd-3.4.2-1.el9

How reproducible:
100%, when the affected pool was created with a stratisd version of 3.3 or earlier.

Steps to Reproduce:
1. Create a keyfile, saved in "testkey.txt", and set a key description for it:
# stratis key set --keyfile-path ./testkey.txt testkey1

2. Using an older version of stratisd (this was reproducible with stratisd-3.2.2-1.el9), and with a test block device (this example uses "/dev/vdb"), create an encrypted pool using the key description created in step 1:
# stratis pool create --key-desc testkey1 spool1 /dev/vdb

3. Stop the pool.
# stratis pool stop spool1

4. Stop the stratis daemon.
# systemctl stop stratisd

5. Update to the version of stratisd with the issue:
# dnf install stratisd-3.4.2-1.el9.x86_64.rpm stratis-cli-3.4.0-1.el9.noarch.rpm

6. Start stratisd.
# systemctl start stratisd

Actual results:
stratisd[32818]: [2022-12-14T18:38:28Z DEBUG stratisd::engine::strat_engine::backstore::crypt::shared] LUKS2 token in the Stratis token slot does not appear to be a Stratis token: Stratis token is missing key 'pool_name' or the value is of the wrong type.

Expected results:
The encrypted pool is able to be started with no issues, when provided by its pool UUID, and with the proper key description loaded in the kernel keyring (i.e.: the key description is visible when running "stratis key list":)

# stratis key list
Key Description
testkey1       

# stratis pool start --uuid fb6779af-0bf2-46f2-9f6d-247683e98854 --unlock-method keyring

Additional info: