Replace bronze with Premium in Issue Weight callout

What does this MR do?

Replaces bronze with Premium in a callout in Issue Weight on Issue detail.

Screenshots (strongly suggested)

before	after
	Impossible to reproduce on dev environment

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have not included a changelog entry because marketing work of Enterprise Edition.
• Code review guidelines
• Style guides
• Separation of EE specific content

Closes #327065 (closed)