[2.26.x] Remove traces of old preference store

[glenhein]

What does this PR do?

Remove old preference store.

Who is reviewing it?

Select relevant component teams:

Ask 2 committers to review/merge the PR and tag them here.

How should this be tested?

Build with a downstream project and make sure everything starts up as expected.

Any background context you want to provide?

What are the relevant tickets?

Fixes: #____

Screenshots

Checklist:

• [ ] Documentation Updated
• [ ] Update / Add Threat Dragon models
• [ ] Update / Add Unit Tests
• [ ] Update / Add Integration Tests

Notes on Review Process

Please see Notes on Review Process for further guidance on requirements for merging and abbreviated reviews.

Review Comment Legend:

• ✏️ (Pencil) This comment is a nitpick or style suggestion, no action required for approval. This comment should provide a suggestion either as an in line code snippet or a gist.
• ❓ (Question Mark) This comment is to gain a clearer understanding of design or code choices, clarification is required but action may not be necessary for approval.
• ❗ (Exclamation Mark) This comment is critical and requires clarification or action before approval.

[jlcsmith]

build now

[cxddfbot]

Internal build has been started, your results will be available at build completion.

[cxddfbot]

Build SUCCESS See the job results in legacy Jenkins UI or in Blue Ocean UI.