ESQL: Refine PipelineBreaker interface

[alex-spies]

We use the PipelineBreaker interface to mark plans that need to (partially) run on the coordinator.

This is especially important for planning of remote ENRICH (relates #115897) and remote LOOKUP JOINs.

• We need to refine this interface to include nodes that can sometimes require to run on the coordinator, like ENRICH _coordinator:policy, or LIMIT - unless PushDownAndCombineLimits duplicated the limit past an MV_EXPAND or LOOKUP JOIN.
• We probably need to mark FORK with this interface.
• We can then refine the validations for remote ENRICH (https://github.com/elastic/elasticsearch/pull/131426/files/444b8f325f79d41fed803db2dbe02771ef7b7187#r2214084695) and remote LOOKUP JOIN (Remote Lookup Join implementation #129013 (comment)).

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[alex-spies]

I think this is addressed with #132205 by @smalyshev . Thanks @smalyshev !

We may iterate on this interface by including limits into it, but we should review that in the light of the validations required for remote enrich.