Disable endowment:long-running in stable

[ritave]

#945 requires rethinking a new API to allow useful Snap use-cases that used this behaviour before.

It's important to support those case, but we also want to avoid scope creep for v1.0.0 release of Snaps.

Outcome

• Disable endowment:long-running in stable altogether and post a deprecation warning in Flask
• Add a console warning when using that permission in Flask explaning the deprecation and pointing to a github issue / discussion.

[FrederikBolding]

Do we just want to remove it in its entirety until we come up with a new solution? Otherwise, we will have to maintain it even though it isn't in use.

[FrederikBolding]

We agreed in a prioritization call to disable for now in stable and remove all together once we have a replacement API.

[GuillaumeRx]

Use the new SnapController arg excludedPermissions introduced in #1125 to retrict it on the extension side.

[FrederikBolding]

Closing for now since it is technically fenced correctly, but we should remember to keep the fencing as-is when we remove the Flask fencing.