[ISSUE-4323][Bug] Fix flink conf path recovery

[hutiefang76]

What changes were proposed in this pull request

Issue Number: close #4323

Related #4316.

This pull request fixes the Flink Conf view path when t_flink_env.flink_conf contains the Flink home path instead of the compressed config content. In that case DeflaterUtils.unzipString fails before the page can render the config.

The recovery is intentionally conservative: it only reloads the config from flinkHome when the stored value equals, or normalizes to, the configured Flink home path. Other invalid compressed values still fail as before.

Brief change log

• Reuse one Flink conf YAML resolver for convertFlinkYamlAsMap, unzipFlinkConf, and getFlinkConfig.
• Recover historical flink_conf values that were stored as the Flink home path by calling the existing doSetFlinkConf flow.
• Add FlinkEnvTest coverage for exact path recovery, trailing slash recovery, and getFlinkConfig usage.

Verifying this change

This change added tests and can be verified as follows:

• Added FlinkEnvTest to cover the recovery behavior.
• Ran JAVA_HOME=$(/usr/libexec/java_home -v 17) ./mvnw -Pfast -pl streampark-console/streampark-console-service -am -DskipTests=false -Dcheckstyle.skip=true -Dtest=FlinkEnvTest -Dsurefire.failIfNoSpecifiedTests=false test
• Ran JAVA_HOME=$(/usr/libexec/java_home -v 17) ./mvnw -pl streampark-console/streampark-console-service -DskipTests spotless:check
• Ran git diff --check and git diff --cached --check

Does this pull request potentially affect one of the following parts

• Dependencies (does it add or upgrade a dependency): no

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud