Fix RedisModule_IsAOFClient Redis Module API

[YaacovHazan]

Since the API declared (as #define) in redismodule.h and uses
the CLIENT_ID_AOF that declared in the server.h, when
a module will want to make use of this API, it will get a compilation
error (module doesn't include the server.h).

The API was broken by d6eb3af (failed attempt for a cleanup).
Revert to the original version of RedisModule_IsAOFClient
that uses UINT64_MAX instead of CLIENT_ID_AOF

[oranagra]

looking back at the history, i see that the original commit that added this API actually did work: 97f6e31
but it was later broken by d6eb3af
i see that the commit that broke it only exists in 6.2, so if we want to keep being compatible with pre-6.2 modules that might have used it, we need to just revert that one line in redismodule.h.
note that modules that were compiled against and old header file currently still work with redis 6.2, is just that they'll fail to build against a 6.2 header file.
@guybe7 is there any reason not to revert that change you did in redismodule.h? the commit comment doesn't explain it, so i suppose it was just a failed attempt for a cleanup.

[guybe7]

Yes, a failed cleanup attempt :(
But TBH I prefer what Yaacov did

[oranagra]

i don't think we can afford it due to backward forward compatibility.