Change build structure to not include tags in each file

[decentralgabe]

The library we're using for secp256k1 keys in JWTs requires a go build tag to access the key type.
This results in //go:build jwx_es256k being added to many files in the codepath of accessing that key type.

We should figure out a way to not need to include this tag in so many packages/files, or consumers of this SDK.

[decentralgabe]

Fixed by removing tags and setting a GoLand constraint for all tests.