fix(dashboard): clarify unverified-email copy for dialog and trial modal

[mekilis]

Summary

• Update verify-email dialog copy to: "Verify your email to continue using Convoy."
• Use the same line in the cloud trial modal when email is unverified (button stays disabled).

Test plan

• Unverified user sees the new dialog copy from the email reminder chip
• Cloud trial modal shows the same line and Start free trial stays disabled until verified

[cursor]

Current version of PR was reviewed by /review-bugbot with additional instructions on Jul 21, 13:21 GMT+1. It flagged 0 findings.

^{Bugbot on commit b12fca1 is skipped.}