add import segment list endpoint

[bcb37]

No description provided.

[zackcl]

@bcb37 I'm working on the Segment Import List modal (#2335) and was wondering if we also need '/segments/lists/import/validation' endpoint like Feature Flag:

validateFeatureFlagList: '/flags/lists/import/validation',
importFeatureFlag: '/flags/import',
importFeatureFlagList: '/flags/lists/import',

[bcb37]

@bcb37 I'm working on the Segment Import List modal (#2335) and was wondering if we also need '/segments/lists/import/validation' endpoint like Feature Flag:

validateFeatureFlagList: '/flags/lists/import/validation',
importFeatureFlag: '/flags/import',
importFeatureFlagList: '/flags/lists/import',

We can just use the segment validation endpoint for that. No need for a separate one, I don't think.

[danoswaltCL]

@zackcl are we good to merge this one?