Add some static data to the store dump test suite

[teh-cmc]

I cannot reproduce https://github.com/rerun-io/rerun/issues/6094, see https://github.com/rerun-io/rerun/issues/6094#issuecomment-2084709242:

I actually cannot repro this. I tried:

• Saving entire timeline, 0.15.1
• Saving time selection, 0.15.1
• Saving entire timeline, main
• Saving time selection, main

For now the best I can think of is to add some static data to the test suite and call it a day...

~Marking as do not merge until the situation is clarified.~

• Closes https://github.com/rerun-io/rerun/issues/6094

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