fix(amazonq): Handle developer profile migration more gracefully

[opieter-aws]

Problem

The cached/persisted Q Developer Profile selection is stored as a map of {connectionID: RegionProfile}, where connectionID is a randomUUID. When migrating to Flare auth, we move away from the concept of a connectionID, and we do not have access to the latest ID of a user. The result is that we cannot restore the user's last selected region profile, and always need users who update versions to make a profile selection.

Solution

To handle this more gracefully, we will:

• Use regionProfile if matching auth profile name (existing logic)
• If no match, check if there is only a single RegionProfile stored in lastUsed. If so, use that one
• If no match, and multiple RegionProfiles are stored in lastUsed cache, make user select

Unit tests added

---

• Treat all work as PUBLIC. Private feature/x branches will not be squash-merged at release time.
• Your code changes must meet the guidelines in CONTRIBUTING.md.
• License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[github-actions]

• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
  • Note: beta or "experiment" features that have active users should announce fixes in the changelog.
  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.