fix: all time interval derivation

[briangregoryholmes]

This PR fixes an issue with combinedTimeRangeSummaryStore where it was initially returning an interval starting at the Unix epoch and ending at the current system time. This valid (though inaccurate) interval would cause the components to initialize their data queries rather than wait for the accurate reference interval.

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!