[query] Remove jackson string length restriction in Spark/Local backends

[chrisvittal]

As mentioned in #14580, IR can get quite big, especially as it can contain an arbitrary amount of encoded literals from the user's python session.

Tested manually, by making a very very large literal, running a pipeline with it on 0.2.132, observing the failure seen in #14650, then running the same pipeline with this change, and it succeeds as normal.

Resolves #14650

[ehigham]

Can you comment about how you've tested this? I think it might also be worth commenting in the source code why/in what circumstances strings might get so long?

As an aside, do you know why strings are getting so crazy long? Is that legit?

[chrisvittal]

@ehigham Think I've addressed everything.

[ehigham]

Thanks for adding the comments - that'll be helpful when reviewing this code in the future no doubt!

[patrick-schultz]

I'm a bit concerned about the replication, and in the future making a change and forgetting to apply it in all three places. Instead of doing this in the apply methods for each backend (and main for the service backend), could we move it to the constructor of the Backend superclass?

[patrick-schultz]

Nice, thanks Chris!