feat(Indexes): getIndexValue

[ShaMan123]

Description

Expose getIndexValues so it is easy to run inverse lookups using getInverseIndexEntry

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following:

• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Follow the Conventional Commits v1.0.0 standard for PR naming (e.g. feat(examples): add hello-world example).
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[ShaMan123]

What do you think about making the methods generic so that:

model.getIndexValues<string>(indexName) satisfies string[]