Update invader core-related constants to their actual values

[tiennou]

Just found out a couple mismatches, none of which are important except INVADER_CORE_EXPAND_TIME which is keyed by the core's level now, thus breaking.

Checklists

• [x] Test passed
• [x] Coding style (indentation, etc)
• [x] Edits have been made to src/ files not index.d.ts
• [x] Run npm run dtslint to update index.d.ts

[tiennou]

Thanks!