Fix Function annotation support to properly handle single result Function return types [DATAGEODE-119]

[spring-projects-issues]

John Blum opened DATAGEODE-119 and commented

Currently, the SDG Function annotation support does not properly inspect the return type of the Function interface method execution, identifying single return type values.

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No further details from DATAGEODE-119

[jxblum]

I am not 100% for certain, but I think @yozaner1324 may have already fixed this issue. Need to verify.

[yozaner1324]

Definitely verify that it's fixed, but I do remember working on this a couple years ago.