[GH-2640] Simplify warning messages of SedonaContext.create()

[jiayuasu]

Did you read the Contributor Guide?

• Yes, I have read the Contributor Rules and Contributor Developer Guide

Is this PR related to a ticket?

• Yes, and the PR name follows the format [GH-XXX] my subject. Closes Simply the warning messages of SedonaContext.create() #2640

What changes were proposed in this PR?

When SedonaContext.create() is called a second time, it prints warning messages about functions and UDTs being already registered. This was partially fixed for ST functions but RS functions and UDT registrations still produced warnings.

This PR adds existence checks before registering:

1. RS aggregate functions (RS_Union_Aggr): Check functionRegistry.functionExists() before calling sparkSession.udf.register() in RasterRegistrator
2. UDT types (Geometry, Geography, SpatialIndex, GridCoverage2D): Check UDTRegistration.exists() before calling UDTRegistration.register() in UdtRegistratorWrapper and RasterUdtRegistratorWrapper
3. Viz UDT types (ImageSerializableWrapper, Pixel): Same check in viz UdtRegistratorWrapper

How was this patch tested?

Tested by calling SedonaContext.create() twice and verifying no warning messages are produced. Also ran all 166 raster algebra tests to ensure RS functions remain functional.

Did this PR include necessary documentation updates?

• No, this PR does not affect any public API so no need to change the documentation.

[Copilot]

Pull request overview

This PR addresses repeated-registration warnings emitted when SedonaContext.create() is invoked multiple times by adding “already registered” guards for raster aggregate UDFs and several UDT registrations.

Changes:

• Guard Sedona Viz UDT registration (ImageSerializableWrapper, Pixel) with UDTRegistration.exists.
• Refactor Sedona SQL UDT registration (Geometry, Geography, SpatialIndex) to register only if missing.
• Guard raster UDT registration and raster aggregate UDAF registration to avoid duplicate function registration warnings.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
spark/common/src/main/scala/org/apache/spark/sql/sedona_viz/UDT/UdtRegistratorWrapper.scala	Adds UDTRegistration.exists checks before registering viz UDTs.
spark/common/src/main/scala/org/apache/spark/sql/sedona_sql/UDT/UdtRegistratorWrapper.scala	Adds a helper to conditionally register core Sedona SQL UDTs only when missing.
spark/common/src/main/scala/org/apache/spark/sql/sedona_sql/UDT/RasterUdtRegistratorWrapper.scala	Adds UDTRegistration.exists guard for raster UDT registration.
spark/common/src/main/scala/org/apache/sedona/sql/RasterRegistrator.scala	Checks the function registry before registering the raster aggregate UDAF to avoid duplicate-registration warnings.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.