fix(test): prioritize "too short" over AFK detection for very short tests (@openvaibhav)

[openvaibhav]

Description

Single word custom tests (e.g. "a" or "I") were incorrectly flagged as
"AFK detected" instead of "too short".

This happens because AFK validation was evaluated before the
"too short" validation inside the result checks chain.

Since both checks exist in the same "else if" chain, the first match wins.
Very short completed tests therefore triggered AFK before the
"too short" condition was reached.

This PR reorders the validation so that "too short" is evaluated
before AFK detection.

Reproduction

1. Go to custom mode
2. Set word count to 1
3. Complete a test with word "a" or "I"
4. Observe incorrect AFK message

After Fix

The test correctly shows:

Test invalid - too short

instead of:

Test invalid - AFK detected

Technical Notes

No logic was modified, only validation priority was adjusted.
Duration mismatch and difficulty checks remain unaffected.

Checks

• Adding quotes?
  • Make sure to include translations for the quotes in the description (or another comment) so we can verify their content.
• Adding a language?
  • Make sure to follow the languages documentation
  • Add language to packages/schemas/src/languages.ts
  • Add language to exactly one group in frontend/src/ts/constants/languages.ts
  • Add language json file to frontend/static/languages
• Adding a theme?
  • Make sure to follow the themes documentation
  • Add theme to packages/schemas/src/themes.ts
  • Add theme to frontend/src/ts/constants/themes.ts
  • (optional) Add theme css file to frontend/static/themes
  • Add some screenshots of the theme, especially with different test settings (colorful, flip colors) to your pull request
• Adding a layout?
  • Make sure to follow the layouts documentation
  • Add layout to packages/schemas/src/layouts.ts
  • Add layout json file to frontend/static/layouts
• Adding a font?
  • Make sure to follow the fonts documentation
  • Add font file to frontend/static/webfonts
  • Add font to packages/schemas/src/fonts.ts
  • Add font to frontend/src/ts/constants/fonts.ts
• Check if any open issues are related to this PR; if so, be sure to tag them below.
• Make sure the PR title follows the Conventional Commits standard. (https://www.conventionalcommits.org for more info)
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Closes #7518