Shooting transcription doesn't add polynomial controls to timeseries

[kaushikponnapalli]

Description

Cannot currently request the timeseries output of a polynomial_control variable like we can a control

Example

In the test case `test_brachistochrone_explicit_shooting_polynomial_control` located in `transcriptions > explicit_shooting > test > test_explicit_shooting.py` adding the line
`theta = prob.get_val('phase0.timeseries.polynomial_controls:theta')` will cause the test to fail with the error
`KeyError: '<model> <class Group>: Variable "phase0.timeseries.polynomial_controls:theta" not found.'`

Dymos Version

1.6.1-dev

Relevant environment information

No response