Validate empty Show On Map options

[vetrovk]

Fixes #2421.

This change rejects empty Show On Map input format and delimiter values through ingredient metadata validation, so empty options return normal validation errors instead of reaching internal coordinate parsing and leaking a TypeError.

Changes:

• add allowEmpty: false to Input Format
• add allowEmpty: false to Input Delimiter
• add regression coverage for empty input format and empty delimiter with Auto format

Validation:

• env PATH="/opt/homebrew/opt/node@24/bin:$PATH" npm ci
• env PATH="/opt/homebrew/opt/node@24/bin:$PATH" npx grunt configTests
• focused Show On Map operation test: 4/4 passed
• full operation tests: 2058/2058 passed
• env PATH="/opt/homebrew/opt/node@24/bin:$PATH" npm run lint
• git diff --check

Notes:

• Work was done in the clean checkout /Users/kirillvetrov/Documents/New project/CyberChef-2421 because the older CyberChef checkout has a corrupted remote ref.

[C85297]

Thank you for your contribution!