[GLib] Add garrow_chunked_array_get_value_data_type() and garrow_chunked_array_get_value_type()

[asfimport]

Reporter: Kouhei Sutou / @kou
Assignee: Kouhei Sutou / @kou

PRs and other links:

• GitHub Pull Request #1458

_{Note: This issue was originally created as ARROW-1970. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 1458
#1458