Handle undefined data interval in grid runs

[bbovenzi]

Continuation of #22999

Use dataIntervalStart and a backup of executionDate for dag run tooltips.
Hide data interval text if it is not defined.

Before: (Tooltip and details header are different)

After: (they are the same)

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^ Add meaningful description above

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[github-actions]

The PR is likely OK to be merged with just subset of tests for default Python and Database versions without running the full matrix of tests, because it does not modify the core of Airflow. If the committers decide that the full tests matrix is needed, they will add the label 'full tests needed'. Then you should rebase to the latest main or amend the last commit of the PR, and push it with --force-with-lease.