Check for other title/name possibilities if title is empty on geojson…

[mfarmer-ara]

This adds an empty check to the initial name set for a GeoJsonDataSource. Adding this check allows it to fallback to checking other title/name possibilities a few lines below.

Example

Clicking each polygon in turn:

Current behavior (1.111)

• Green = Title is not empty, shows "Actual Title"
• Red = Title is empty and fallback possibility is not considered, shows ""

Changes here

• Green = "Actual Title"
• Red = "Fallback Title"

Closes #11633

[cesium-concierge]

Thank you so much for the pull request @mfarmer-ara! I noticed this is your first pull request and I wanted to say welcome to the Cesium community!

The Pull Request Guidelines is a handy reference for making sure your PR gets accepted quickly, so make sure to skim that.

• ❌ Missing CONTRIBUTORS.md entry.
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[ggetz]

Thanks @mfarmer-ara. We'll need a Contributor License Agreement (CLA) in order to review this PR. Can you please submit one and comment back here once that's done?

[mfarmer-ara]

I've sent a request to my company to get it filled out (yesterday). With the holiday this week it may be a little delayed. I'll revisit the remaining tasks as soon as it's sorted!

[mfarmer-ara]

@ggetz I've updated the contributors file and received word that our team sent in the agreement for review.