Fix/block on pebble timeout

[seb4stien]

Avoid to go in error state on pebble timeout.

[seb4stien]

@weiiwang01 WDYT of this PR?

[weiiwang01]

@weiiwang01 WDYT of this PR?

I don't object to this pull request, but I don't think this pull request solves the fundamental cause of this issue.

Also the pebble timeout problem can't be solved with methods within the typical juju operations, but instead it needs some hack to solve it (for now it needs to clear the pebble storage with juju exec, then a pod deletion with kubectl), so the block state doesn't perfectly fit the situation here.

And, even if we patch this problem in the opencti connector charms, the problem still exists in the opencti charm. And from past experience, this problem not only affects the add_layer api endpoint, but also other pebble endpoints, so it's more difficult to wrap them all with a try catch.