fix: Floating title content incorrect for multi-sources (#17274)

[keithchong]

@saumeya found a bug when reviewing my PR and the fix should be separate since it is against the initial PR changes that added the new Sources tab and related source cards.

There is no Issue reported for this but the problem is that the wrong source is used when populating the contents of the floating title. This small change will fix it. See screenshot below.

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• The title of the PR conforms to the Toolchain Guide
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).
• My new feature complies with the feature status guidelines.
• I have added a brief description of why this PR is necessary and/or what this PR solves.
• Optional. My organization is added to USERS.md.
• Optional. For bug fixes, I've indicated what older releases this fix should be cherry-picked into (this may or may not happen depending on risk/complexity).

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[bunnyshell]

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[keithchong]

With fix:

[ishitasequeira]

/cherry-pick release-2.12