Fix my own mistake in the last PR (unitycatalog#242)

**PR Checklist**

- [x] A description of the changes is added to the description of this
PR.
- [ ] If there is a related issue, make sure it is linked to this PR.
- [ ] If you've fixed a bug or added code that should be tested, add
tests!
- [ ] If you've added or modified a feature, documentation in `docs` is
updated

**Description of changes**

In unitycatalog#151 I made a mistake and it was before duckdb tests were introduced.
This PR is a fix.

@ravivj-db Sorry, it was may mistake. May you take a look, please?

server/src/test/java/io/unitycatalog/server/utils/PopulateTestDatabase.java

@@ -282,7 +282,7 @@ public static void main(String[] args) throws JsonProcessingException {
     // Add columns
     ColumnInfoDAO firstName = ColumnInfoDAO.builder()
         .name("first_name")
-        .typeName(ColumnTypeName.STRUCT.getValue())
+        .typeName(ColumnTypeName.STRING.getValue())
         .comment("string column")
         .ordinalPosition((short) 0)
         .build();