java-client: use FetchTableRequests to stop cascading behavior

[devinrsmith]

This graph shows how the java client currently constructs a request from a linear TableSpec of three operations that each have an export:

flowchart RL
    C --> B --> A

    e1[[export: 1]] --> A
    e2[[export: 2]] --> B
    e3[[export: 3]] --> C

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Unfortunately, I think I've misinterpreted how cascading works, and assumed it only applied to CANCELLED (see #4781, #5002) - it also applies to RELEASED afaict. (It's also possible the behavior changed during #4772, but I haven't dug into that aspect.)

Regardless, it may be necessary for correctness for the java client to introduce a layer of Fetch's so that RELEASED doesn't cascade - this would fix #4781 and #5002.

flowchart RL
    C --> B --> A
    
    FetchA[Fetch] --> A
    FetchB[Fetch] --> B
    FetchC[Fetch] --> C

    e1[[export: 1]] --> FetchA
    e2[[export: 2]] --> FetchB
    e3[[export: 3]] --> FetchC

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It may also be desirable to more explicitly document how export behavior works, and how clients may want to introduce this type of structure to limit cascading cancel/releases.

[nbauernfeind]

IMO this should be unnecessary if we find #5014 acceptable. It feels excessive to put this responsibility on client implementations.