### What changes were proposed in this pull request?
This pr fix all 14 failed cases in `external/avro` module in Scala 2.13, the main change of this pr as follow:
- Manual call `toSeq` in `AvroDeserializer#newWriter` and `SchemaConverters#toSqlTypeHelper` method because the object type for case match is `ArrayBuffer` not `Seq` in Scala 2.13
- Specified `Seq` to `s.c.Seq` when we call `Row.get(i).asInstanceOf[Seq]` because the data maybe `mutable.ArraySeq` but `Seq` is `immutable.Seq` in Scala 2.13
### Why are the changes needed?
We need to support a Scala 2.13 build.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
- Scala 2.12: Pass the Jenkins or GitHub Action
- Scala 2.13: Pass 2.13 Build GitHub Action and do the following:
```
dev/change-scala-version.sh 2.13
mvn clean install -DskipTests -pl external/avro -Pscala-2.13 -am
mvn clean test -pl external/avro -Pscala-2.13
```
**Before**
```
Tests: succeeded 197, failed 14, canceled 0, ignored 2, pending 0
*** 14 TESTS FAILED ***
```
**After**
```
Tests: succeeded 211, failed 0, canceled 0, ignored 2, pending 0
All tests passed.
```
Closes#29801 from LuciferYang/fix-external-avro-213.
Authored-by: yangjie01 <yangjie01@baidu.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
664a1719de