perf: batcher no-dict lookup for (Un)Reliable

[imerr]

Dict lookup uses 6% in an il2cpp build for 121 nts, this ugly patch brings that down to 0.x%

I don't like this from a code perspective, so lets talk if there's a better way

Do people actually use channel ids that are big? We could do an array lookup instead with the channelId as index if they dont
Or looping over a list to find the channel by id should be faster than using a Dict for 2 (or a handful) of values
Allowing more than the 2 default channels might be useful for some people, so I wouldnt advocate removing them outright

Bleh.

[imerr]

Profiler screenshots:

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