[metastore] Fields in nested column have a leading comma when preceded by array in type struct

In the Hive assist panel (in Hive Editor, Metastore, etc.), if you are navigating to a nested column to look at the fields, if a field in the nested column is preceded by a field that has a type of array like:

fieldname:array<bigint>

...then the field directly following that one will have a comma preceding the field name in the assist panel like:

,fieldname

The fieldname is also not callable in the Editor autocomplete due to this. However queries still work fine (using "fieldname" and not ",fieldname"), and running a DESCRIBE query on the nested column shows the field name correctly as "fieldname" instead of ",fieldname". So Hue is not parsing out the preceding comma when the preceding field is an array type.

An example type for a nested column where this kind of problem is caused is a type like:

struct<fieldname1:bigint,fieldname2:int,fieldname3:int,fieldname4:array<bigint>,fieldname5:bigint,fieldname6:array<struct<array_elem:string>>,fieldname7:string>

In the case of the above type, it will look like the following in the assist panel:

fieldname1
fieldname2
fieldname3
fieldname4
,fieldname5
fieldname6
,fieldname7

...when it should look like:

fieldname1
fieldname2
fieldname3
fieldname4
fieldname5
fieldname6
fieldname7