Drop async-list-label action

[ktf]

My understanding is that this is not actually used, as it is superseded by
the two / three tag approach.

[github-actions]

REQUEST FOR PRODUCTION RELEASES:
To request your PR to be included in production software, please add the corresponding labels called "async-" to your PR. Add the labels directly (if you have the permissions) or add a comment of the form (note that labels are separated by a ",")

+async-label <label1>, <label2>, !<label3> ...

This will add <label1> and <label2> and removes <label3>.

The following labels are available
async-2023-pbpb-apass4
async-2023-pp-apass4
async-2024-pp-apass1
async-2022-pp-apass7
async-2024-pp-cpass0
async-2024-PbPb-apass1
async-2024-ppRef-apass1
async-2024-PbPb-apass2
async-2023-PbPb-apass5

[ktf]

@alcaliva @catalinristea can you confirm you do not actually use the action and its results?

[ktf]

@sawenzel am I right?

[sawenzel]

@ktf: In principle, for what concerns the MC part (1st tag in the 2tag approach) these labels do no longer make sense.
However, we might still cherry-pick commits onto releases for the async software tag (2nd tag in the 2tag approach).

From my part we can take this away but I let DPG comment concerning how they prefer to organize cherry-picks for the 2nd tag.

[alcaliva]

You can remove it as it is obsolete now