Do something instead of silently ignoring invalid plugin in MenuLinkManager

Problem/Motivation

Brought up in #2301239: MenuLinkNG part1 (no UI or conversions): plugins (static + MenuLinkContent) + MenuLinkManager + MenuTreeStorage → , why are we silently ignoring invalid plugin ids. There might have been a decision before to do something.

See MenuLinkManager::getDefinitions()

Proposed resolution

Do something

Remaining tasks

Remember what we said the plan was for what to do.

User interface changes

No.

API changes

No?

Postponed until

#2256521: [META] New plan, Phase 2: Implement menu links as plugins, including static admin links and views, and custom links with menu_link_content entity, all managed via menu_ui module →