[avalanche] Remove the network bypass flag, make it default for avalanche outbounds

Summary:
This diff removes the -bypassnetgrouplimit flag in favor of a permanent bypass for the avalanche outbounds. It also fixes a couple issues that are preventing connecting non avalanche outbounds after we connected enough avalanche peers:

• The outbound type counters have fallthrough path that cause the non avalanche outbound count to be wrong.
• The group limit should still apply to non avalanche peers in the fallback case, when we couldn't find an avalanche peer.

Depends on D11833.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, sdulfari

Reviewed By: #bitcoin_abc, sdulfari

Subscribers: sdulfari

Differential Revision: https://reviews.bitcoinabc.org/D11829