Fix some of TS typing issues

[azygis]

Description

Types for features property is wrong on vector source amongst some other places. This PR is making them right.

Motivation and Context

Fixes #399.

How Has This Been Tested?

vitest and playwright tests have been run. Typings should not impact the functionality itself though.

Types of Changes

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Tests
• Other (Tooling, Dependency Updates, etc.) - TS typings

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I added a new test.

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