[SPARK-34261][SQL] Avoid side effect if create exists temporary function

[ulysses-you]

What changes were proposed in this pull request?

Add function exists check before load resource.

Why are the changes needed?

We should not add jar into classpath if the create temporary function is already exists.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Add test.

[SparkQA]

Kubernetes integration test starting
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[SparkQA]

Kubernetes integration test status failure
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[SparkQA]

Test build #134543 has finished for PR 31358 at commit da3e7b3.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/39141/

[SparkQA]

Kubernetes integration test status success
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[srowen]

It seems fine to me if this doesn't change behavior, just fails earlier.

[SparkQA]

Test build #134555 has finished for PR 31358 at commit 590b0b3.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[ulysses-you]

thanks @srowen , also cc @maropu @cloud-fan

[maropu]

Thanks! Merged to master.

[ulysses-you]

thanks for merging !