Add ddt to test-random group

[1ucian0]

Since #15619, randomized testing had been failing because ddt is not installed:

This adds "ddt>=1.2.0" to the test-random group to bring randomized testing back.

AI/LLM disclosure

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[qiskit-bot]

One or more of the following people are relevant to this code:

• @Qiskit/terra-core