[KYUUBI #6813] [BUILD] Replace java.version 1.8 with 8

# 🔍 Description
## Issue References 🔗

This pull request fixes #

## Describe Your Solution 🔧

- fix the compilation error on Zulu JDK8 (Zulu 8.82.0.21-cA-macos-aarch64 with M4 Max chip on MacOS 15.1), when running `build/mvn clean install -pl :kyuubi-util -DskipTests -am` command to build a pure Java module,  by replacing version code sytle from 1.8 to 8.

![image](https://github.com/user-attachments/assets/d4d473b5-8db7-49cf-b7d5-6cc23541496c)

## Types of changes 🔖

- [ ] Bugfix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)

## Test Plan 🧪

#### Behavior Without This Pull Request ⚰️

#### Behavior With This Pull Request 🎉

#### Related Unit Tests

---

# Checklist 📝

- [ ] This patch was not authored or co-authored using [Generative Tooling](https://www.apache.org/legal/generative-tooling.html)

**Be nice. Be informative.**

Closes #6813 from bowenliang123/java8.

Closes #6813

1a1e3f3 [Bowen Liang] set java.version to 8

Authored-by: Bowen Liang <[email protected]>
Signed-off-by: Cheng Pan <[email protected]>

pom.xml

@@ -113,7 +113,7 @@
     </distributionManagement>
 
     <properties>
-        <java.version>1.8</java.version>
+        <java.version>8</java.version>
         <maven.version>3.9.9</maven.version>
         <maven.compiler.source>${java.version}</maven.compiler.source>
         <maven.compiler.target>${java.version}</maven.compiler.target>
@@ -1901,10 +1901,10 @@
         <profile>
             <id>java-8</id>
             <activation>
-                <jdk>1.8</jdk>
+                <jdk>8</jdk>
             </activation>
             <properties>
-                <java.version>1.8</java.version>
+                <java.version>8</java.version>
                 <iceberg.version>1.6.1</iceberg.version>
             </properties>
         </profile>