[5.x] Fix JobWatcher when processing deleted instance of SerializesModels

[hapidjus]

If there is a failure when unserializing the command, (for instance if the job deleted a model it received, of the database connection is set dynamically) the jobs will never proceed to processed. See #1479

In this PR unserialize is removed in favor of preg_replace to extract the batch_id

[crynobone]

@hapidjus shouldn't we use the new approach only if unserialize() return an exception?

[hapidjus]

@hapidjus shouldn't we use the new approach only if unserialize() return an exception?

Makes sense.
This PR was mainly to confirm that using preg_match is a reasonable approach here.
The PR currently doesn’t handle encrypted data or include any tests.

However I'm not sure we can catch exceptions that happens "inside" the unserialize function. It's not necessarily unserialize() that throws.

[hapidjus]

I've updated the PR now to try to unserialize first and only use preg_match as fallback.

[crynobone]

@hapidjus Thanks, I'll review it and possibility add some tests to cover the new use case. Will mark it as ready when I'm done with it

[hapidjus]

I understrand that catch (\Exception|\Error) is a bit greedy. But there are other ways that the unserialize can go wrong. For instance when in a multi tenancy context and the database connection has not been set yet. See this issue for instance archtechx/tenancy#1263