#11600

## Description of change

Merge 2.8-rc branch with these commits:

#11585 don't write errors when pubsub socket disconnects
#11583 k8s pod initialisaton races
#11582 increase max wait time for WaitAdance
#11573 finish legacy lease removal
#11591 increase timeout in machine agent tests
#11592 expose engine worker restart time as package variable
#11507 add k8s model agent pod
#11595 fix caas uniter restart on error
#11593 add revoke leases so dead units lose their lease immediately
#11594 fix deferreturn and bolt
#11599 update deployment name used for model op

## QA steps

See individual PRs.

#11604

## Description

Merge 2.8 branch with these commits:

#11585 don't write errors when pubsub socket disconnects
#11583 k8s pod initialisaton races
#11582 increase max wait time for WaitAdance
#11573 finish legacy lease removal
#11591 increase timeout in machine agent tests
#11592 expose engine worker restart time as package variable
#11507 add k8s model agent pod
#11595 fix caas uniter restart on error
#11593 add revoke leases so dead units lose their lease immediately
#11594 fix deferreturn and bolt
#11599 update deployment name used for model op

## QA

Se individual PRs

…t-least-384-bytes-long

#11660

## Description of change

This PR lands a number of changes to unblock our CI. More specifically:

- Go will not allow TLS handshakes with TLS1.2+ if key is 64 bytes long. This PR removes the PatchValue calls from the various test suites that forced a 512bit key length so that all our tests use the preferred (384 byte long) default key size.
- In addition, this PR cherry-picks a commit from #11632 to fetch a snapshot of the vendor folder from S3 and includes additional commits to bypass 'dep ensure' (which is called multiple times by the various Makefile targets) when using the cached deps.
- Finally, the PR backports the fixes from #11654 and #11594.