Time Grain control is not visible for legacy visualization types in case GENERIC_CHART_AXES is enabled

[Vitor-Avila]

The TIME GRAIN control is no longer visible in Explore for legacy visualization types such as the Line Chart (legacy) and the Time-Series Bar Chart (legacy).

How to reproduce the bug

1. Make sure that GENERIC_CHART_AXES is enabled in your testing environment.
2. Create a new chart using any dataset and the Line Chart (legacy) visualization type.

Expected results

The time grain control should be visible in the Time settings section.

Actual results

The field is not visible:

Environment

• browser type and version: Chrome latest version
• superset version: Runningmaster
• any feature flags active: GENERIC_CHART_AXES

Checklist

• I have checked the superset logs for python stacktraces and included it here as text if there are any.
• I have reproduced the issue with at least the latest released version of superset.
• I have checked the issue tracker for the same issue and I haven't found one similar.

[Vitor-Avila]

Assessing a potential fix