V1 write API doesn't handle buckets that don't fit the "db/rp" pattern

[danxmoran]

Steps to reproduce:
List the minimal actions needed to reproduce the behavior.

1. Create a test bucket using influx setup
2. Create a test-user V1 token using influx v1 auth create, granting write access on the bucket
3. Attempt to write data using the test-user token and the write API:

curl -u test-user:${TEST_PWD} localhost:8086/write\?db=test -d "cpu foo=10,bar=11"

Expected behavior:
The write should succeed

Actual behavior:
The write fails with a permissions error. Running influx bucket list shows a new test/autogen bucket has been created.

By stepping through the code, I was able to find that the V1 API:

1. Checks if an RP was given in the command, and uses "autogen" if not
2. Checks for the presence of the bucket named "db/rp", creating it if not found
3. Attempts to write into the new bucket

Step 3 fails the auth check because the user is authorized to write into "test", not "test/autogen"

[stuartcarnie]

@danxmoran I believe this will be resolved with #19945

[danxmoran]

If not by that, then I'd expect by #19954

[stuartcarnie]

This is no longer an issue, as we're not auto-creating buckets and DB/RP mappings. We have verified that writes are now working after mappings are setup.