Add title placeholder for new issues

What does this MR do?

Adds Title as the placeholder text for the title input.

Screenshots (if relevant)

Before	After

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer

What are the relevant issue numbers?

Closes #48085 (closed)