feat(vitality): give every survivor one painkiller chance without a hit delay

[Joltras]

Proposed changes

Every survivor can now take their painkillers once per round whenever they want, even right after being hit. While the painkillers are working, every hit reduces the remaining healing, no matter how small it is. Extra hearts at the start of a round are only given in small rounds, which is how they were meant to work.

Types of changes

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Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of
them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before
merging your code.

• I have read the CONTRIBUTING.md
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[github-actions]

Test results

  672 files    672 suites   5m 1s ⏱️
1 516 tests 1 510 ✅  6 💤 0 ❌
4 551 runs  4 533 ✅ 18 💤 0 ❌

Results for commit 0f477d0.