Add a BenchmarkDotNet comparison of Execute/ExecuteAsync vs ExecuteResp/ExecuteRespAsync (#3215)

HSET (32 fields) + HGETALL against a real local server, contrasting the classic
object[]/RedisResult path against ExecuteResp's RedisKeyOrValue/RespResult path. Each
call rents/leases its own buffer rather than sharing one across iterations, to match a
single realistic call rather than an amortized-lease scenario. Field values are plain
integers and field names are precomputed once, so the measured allocation reflects what
Execute/ExecuteResp themselves cost rather than string concatenation in the benchmark
code; both benchmarks return a tally read back from the server as a correctness check
that the two paths agree.

Also re-enables the StackExchange.Redis ProjectReference, previously commented out due
to a supposed AsciiHash conflict that no longer reproduces - the generated AsciiHash
classes are internal and this project has no InternalsVisibleTo access to them.