fix: Correct capitalization in English source string

[AnujRewar]

Fixed capitalization in source translation string

• Changed 'It' to 'it' in 'Create a copy of a course, It should be considered as a new course' message
• Addresses translation issue Translation issue with message Wikimedia:Wikilearn-backend-24c849-Create a copy of a course, It/sv #246

Description

Fixed incorrect capitalization in the source English translation string. The word "it" after a comma should not be capitalized in English unless it's the start of a new sentence or a proper noun.

Before: "Create a copy of a course, It should be considered as a new course"
After: "Create a copy of a course, it should be considered as a new course"

This change ensures proper English grammar and provides a correct base string for all language translations.

Supporting information

• Issue: Translation issue with message Wikimedia:Wikilearn-backend-24c849-Create a copy of a course, It/sv #246 (Wikimedia translation tracking)
• Grammar reference: English capitalization rules after commas
• Impact: Affects all language translations that use this source string

Testing instructions

1. Verify the source string change in the translation files
2. Recompile translations: django-admin compilemessages -l sv (and other languages if needed)
3. Confirm the change propagates to all translated versions

Deadline

None

Other information

This change improves the base translation string, which will benefit all language translations derived from it.