[SPARK-49222][SQL] Clear useless methods in QueryCompilationErrors

### What changes were proposed in this pull request?

Clear useless methods in QueryCompilationErrors

### Why are the changes needed?

Some unused methods in QueryCompilationErrors need to clear

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

Not need

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

No

Closes apache#47740 from xuzifu666/clean_QueryCompilationErrors.

Authored-by: xuyu <11161569@vivo.com>
Signed-off-by: Max Gekk <max.gekk@gmail.com>

common/utils/src/main/resources/error/error-conditions.json

@@ -388,12 +388,6 @@
     ],
     "sqlState" : "58030"
   },
-  "CANNOT_SAVE_VARIANT" : {
-    "message" : [
-      "Cannot save variant data type into external storage."
-    ],
-    "sqlState" : "0A000"
-  },
   "CANNOT_UPDATE_FIELD" : {
     "message" : [
       "Cannot update <table> field <fieldName> type:"

sql/catalyst/src/main/scala/org/apache/spark/sql/errors/QueryCompilationErrors.scala

@@ -203,13 +203,6 @@ private[sql] object QueryCompilationErrors extends QueryErrorsBase with Compilat
     invalidParameter("DOUBLE", "ewm", "alpha", invalidValue)
   }
 
-  def invalidStringParameter(
-      functionName: String,
-      parameter: String,
-      invalidValue: Expression): Throwable = {
-    invalidParameter("STRING", functionName, parameter, invalidValue)
-  }
-
   def invalidParameter(
       subClass: String,
       functionName: String,
@@ -1679,12 +1672,6 @@ private[sql] object QueryCompilationErrors extends QueryErrorsBase with Compilat
       messageParameters = Map.empty)
   }
 
-  def cannotSaveVariantIntoExternalStorageError(): Throwable = {
-    new AnalysisException(
-      errorClass = "CANNOT_SAVE_VARIANT",
-      messageParameters = Map.empty)
-  }
-
   def cannotResolveAttributeError(name: String, outputStr: String): Throwable = {
     new AnalysisException(
       errorClass = "_LEGACY_ERROR_TEMP_1137",