feat: decide TARGET_COMMITTEE_SIZE

[LHerskind]

No description provided.

[LHerskind]

If we target a probability of at most $10^{-6}$ for an attacker with $\frac{1}{3}$ of stake to get super-majority $\lfloor \frac{2}{3} \rfloor + 1$ of a committee we end up with a committee size of $48$ needing $33$ signatures to progress. This gives us a probability at $5.77*10^{-7}$. This is updated in #8122 where the constant was also included.