Support seed=SeedSequence in emitters

[btjanaka]

Description

Previously, passing a SeedSequence as a seed in EvolutionStrategyEmitter and GradientArborescenceEmitter threw an error because SeedSequence cannot be initialized from another SeedSequence. This PR adds checks for SeedSequence so that SeedSequence can be passed in as a seed in these two emitters. Note that in other emitters, the seed is passed directly to the default_rng(), which can handle SeedSequence as input.

Status

• [x] I have read the guidelines in CONTRIBUTING.md
• [x] I have formatted my code using yapf
• [x] I have tested my code by running pytest
• [x] I have linted my code with pylint
• [x] I have added a one-line description of my change to the changelog in HISTORY.md
• [x] This PR is ready to go