[fix][ml] Fix races in ledger initialization timeout handling

[lhotari]

Motivation

There are multiple race conditions in ledger initialization timeout handling. There are also some gaps where the cleanup doesn't happen properly or the timeout handling races with in-progress initialization.

Modifications

• add properly handling for race conditions.

Documentation

• [ ] doc
• [ ] doc-required
• [x] doc-not-needed
• [ ] doc-complete