[Chore] Disable a redundant constraint warning

Description

Michelson.Typed.Sing, raises a redundant constraint warning. However, this went unnoticed because it does so only with some compiler optimization levels.

This disables the redundant constraint warning in said module with a pragma.

For context, this was noticed on production pipelines (where we use a different optimization level) and is a known bug.

Note: this particular warning was expected and it's due to a known TH function shortcoming, see this discussion

Related issue(s)

None

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