TensorBoard.dev : Uploader delete functionality supports more than one experiment_id at a time.

[bileschi]

Motivation for features / changes

#4765

Technical description of changes

Modifies flag to support a comma-separated list of experiment ids (while retaining functionality of just one id)

Screenshots of UI changes

Expected use case:

$ ./bazel-bin/tensorboard/tensorboard dev delete --experiment_id=S0kpfaQeTvaSjCA2nTMQFw,K8vwol4qSoi8UqViDj7q0Q
Deleted experiment S0kpfaQeTvaSjCA2nTMQFw.
Deleted experiment K8vwol4qSoi8UqViDj7q0Q.

No auth:

$ ./bazel-bin/tensorboard/tensorboard dev delete --experiment_id=S0kpfaQeTvaSjCA2nTMQFw,K8vwol4qSoi8UqViDj7q0Q

***** TensorBoard Uploader *****

This will delete the 2 experiments on
https://tensorboard.dev with the following experiment ID:

['S0kpfaQeTvaSjCA2nTMQFw', 'K8vwol4qSoi8UqViDj7q0Q']

You have chosen to delete an experiment. All experiments uploaded
to TensorBoard.dev are publicly visible. Do not upload sensitive
data.

Your use of this service is subject to Google's Terms of Service
<https://policies.google.com/terms> and Privacy Policy
<https://policies.google.com/privacy>, and TensorBoard.dev's Terms of Service
<https://tensorboard.dev/policy/terms/>.

This notice will not be shown again while you are logged into the uploader.
To log out, run `tensorboard dev auth revoke`.

Continue? (yes/NO) no

At least one experiment does not exist

$ ./bazel-bin/tensorboard/tensorboard dev delete --experiment_id=S0kpfaQeTvaSjCA2nTMQFw,K8vwol4qSoi8UqViDj7q0Q
No such experiment S0kpfaQeTvaSjCA2nTMQFw. Either it never existed or it has already been deleted.

Detailed steps to verify changes work correctly (as executed by you)

• Upload new experiment(s) to tb.dev and then try deleting it, from command line.
• Delete an existing experiment
• Delete in a no-auth state
• Delete multiple experimetns
• Delete multiple experiments where one is invalid

Alternate designs / implementations considered

Considered changing the flag name to experiment_id_list or adding a second flag name. This seemed strictly worse than extending the behavior of the existing flag.

[bileschi]

• Internal backend defines a limit of 5 deletions per minute. May want to introduce some padding in the uploader tool to prevent hitting that limit.

• Current implementation stops at first failure - may want to continue to other eids?