Connaisseur should early exit from verification when threshold is met

[dbbhat]

Describe the feature
Connaisseur should early exit from verifying signatures if threshold is met

Optional: Is your feature request related to a problem? Please describe.
We have a validator spec with two keys as trustRoots shown below

- name: cosignvalidator
  type: cosign
  trustRoots:
  - name: connaisseur-key-1
    key: k8s://connaisseur/connaisseur-secret-1
  - name: connaisseur-key-2
    key: k8s://connaisseur/connaisseur-secret-2
  auth: 
    secretName: foo-secret  # reference a k8s secret in the form required by the validator type (check the docs)

and for the imagePolicy, the threshold is set to be 1

- pattern: "<registry>/<foo>/<bar>/*:*"
  validator: cosignvalidator
  with:
    trustRoot: "*"
    threshold: 1
    verifyInTransparencyLog: false

However from the logs, seeing that connaisseur verifies signature wrt both keys specified

{"timestamp": "2023-08-22 20:33:20.361542", "message": "COSIGN output of trust root 'connaisseur-key-1' for image'<registry-foo>:<tag-bar>': RETURNCODE: 0; STDOUT: {\"critical\":{\"identity\":{\"docker-reference\":\"<image-name>\"},\"image\":{\"docker-manifest-digest\":\"sha256:<digest>\"},\"type\":\"cosign container image signature\"},\"optional\":null}\n\n{\"critical\":{\"identity\":{\"docker-reference\":\"<foo>"},\"image\":{\"docker-manifest-digest\":\"sha256:<digest>\"},\"type\":\"cosign container image signature\"},\"optional\":null}\n\n; STDERR: **Warning** Skipping tlog verification is an insecure practice that lacks of transparency and auditability verification for the signature.\n\nVerification for nvcr.io/<foo>:<tag>--\nThe following checks were performed on each of these signatures:\n  - The cosign claims were validated\n  - The signatures were verified against the specified public key\n"}

{"timestamp": "2023-08-22 20:33:20.403335", "message": "COSIGN output of trust root 'connaisseur-key-1' for image'<registry-foo>:<tag-bar>': RETURNCODE: 0; STDOUT: {\"critical\":{\"identity\":{\"docker-reference\":\"<image-name>\"},\"image\":{\"docker-manifest-digest\":\"sha256:<digest>\"},\"type\":\"cosign container image signature\"},\"optional\":null}\n\n{\"critical\":{\"identity\":{\"docker-reference\":\"<foo>"},\"image\":{\"docker-manifest-digest\":\"sha256:<digest>\"},\"type\":\"cosign container image signature\"},\"optional\":null}\n\n; STDERR: **Warning** Skipping tlog verification is an insecure practice that lacks of transparency and auditability verification for the signature.\n\nVerification for nvcr.io/<foo>:<tag>--\nThe following checks were performed on each of these signatures:\n  - The cosign claims were validated\n  - The signatures were verified against the specified public key\n"}

Ideally, I would expect that when a certain threshold is specified, connaisseur should early exit when the threshold is met and not verify wrt all trust roots specified.