[Bug] init connector can not approve ipv6 FE

### Search before asking

- [x] I had searched in the [issues](https://github.com/apache/incubator-doris/issues?q=is%3Aissue) and found no similar issues.

### Version

spark-doris-connector-spark-3.2 25.0.1

### What's Wrong?

my doris fe node is ipv6 address, when i init connector, i config
`.option("doris.fenodes", "[aaaa:bbbb:11:22::33]:8030")`
but it throw an exception

```
py4j.protocol.Py4JJavaError: An error occurred while calling o775.save.
: java.lang.NumberFormatException: For input string: "bbbb"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
at org.apache.doris.spark.client.DorisFrontendClient.lambda$initFrontends$1(DorisFrontendClient.java:145)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)

```

### What You Expected?

connector support ipv6 fe nodes

### How to Reproduce?

_No response_

### Anything Else?

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

Start at org.apache.doris.spark.client.DorisFrontendClient.initFrontends, especially the parsing shown at line 145 in the stack trace. Verify how the bracketed IPv6 value is interpreted and add coverage for the reported doris.fenodes setting; done means an IPv6 FE node initializes without the NumberFormatException.

Written by the indexing model from the issue text.