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GH-43160: [Swift] Add Struct Array (#43161)

### Rationale for this change
Adding StructArray for struct type impl

### What changes are included in this PR?
Added StructArray impl

* GitHub Issue: #43160

Authored-by: Alva Bandy <abandy@live.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>