[SPARK-53818] Improve SentinelResourceState.toString by JEP-280 instead of ToStringBuilder

[dongjoon-hyun]

What changes were proposed in this pull request?

This PR aims to improve SentinelResourceState.toString by JEP-280 instead of ToStringBuilder.

Why are the changes needed?

This is aligned with Apache Spark main repository improvement.

• [SPARK-52880][CORE] Improve toString by JEP-280 instead of ToStringBuilder spark#51572

Since Java 9, String Concatenation has been handled better by default.

ID	DESCRIPTION
JEP-280	Indify String Concatenation

For example, SentinelResourceState.toString is changed like the following by this PR.

BEFORE

  public java.lang.String toString();
    Code:
         0: new           #43                 // class org/apache/commons/lang3/builder/ToStringBuilder
         3: dup
         4: aload_0
         5: invokespecial #45                 // Method org/apache/commons/lang3/builder/ToStringBuilder."<init>":(Ljava/lang/Object;)V
         8: ldc           #48                 // String resource
        10: aload_0
        11: getfield      #17                 // Field resource:Lorg/apache/spark/k8s/operator/BaseResource;
        14: invokevirtual #49                 // Method org/apache/commons/lang3/builder/ToStringBuilder.append:(Ljava/lang/String;Ljava/lang/Object;)Lorg/apache/commons/lang3/builder/ToStringBuilder;
        17: ldc           #53                 // String previousGeneration
        19: aload_0
        20: getfield      #39                 // Field previousGeneration:J
        23: invokevirtual #54                 // Method org/apache/commons/lang3/builder/ToStringBuilder.append:(Ljava/lang/String;J)Lorg/apache/commons/lang3/builder/ToStringBuilder;
        26: ldc           #57                 // String isHealthy
        28: aload_0
        29: getfield      #13                 // Field isHealthy:Z
        32: invokevirtual #58                 // Method org/apache/commons/lang3/builder/ToStringBuilder.append:(Ljava/lang/String;Z)Lorg/apache/commons/lang3/builder/ToStringBuilder;
        35: invokevirtual #61                 // Method org/apache/commons/lang3/builder/ToStringBuilder.toString:()Ljava/lang/String;
        38: areturn

AFTER

  public java.lang.String toString();
    Code:
         0: aload_0
         1: getfield      #17                 // Field resource:Lorg/apache/spark/k8s/operator/BaseResource;
         4: invokestatic  #43                 // Method java/lang/String.valueOf:(Ljava/lang/Object;)Ljava/lang/String;
         7: aload_0
         8: getfield      #39                 // Field previousGeneration:J
        11: aload_0
        12: getfield      #13                 // Field isHealthy:Z
        15: invokedynamic #49,  0             // InvokeDynamic #0:makeConcatWithConstants:(Ljava/lang/String;JZ)Ljava/lang/String;
        20: areturn

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Pass the CIs.

Was this patch authored or co-authored using generative AI tooling?

No.

[dongjoon-hyun]

Thank you, @viirya .

[dongjoon-hyun]

Merged to main.