revert [improvement](mv) Support to use cast when create sync materialized view #38008 (#39378)

## Proposed changes

this is brought by https://github.com/apache/doris/pull/38008
if use cast(FLOOR(MINUTE(time) / 15) as decimal(9, 0)) in group by
clause when sync materialized view. if downgrade from 2.1.6 to 2.1.5 or
upgrade 2.1.6 to 3.0.0
this may cause fe can not run. So revert the function.

fe/fe-core/src/main/java/org/apache/doris/analysis/CreateMaterializedViewStmt.java

@@ -273,9 +273,8 @@ public class CreateMaterializedViewStmt extends DdlStmt {
 
             Expr selectListItemExpr = selectListItem.getExpr();
             selectListItemExpr.setDisableTableName(true);
-            Expr realItem = selectListItemExpr.unwrapExpr(false);
-            if (!(realItem instanceof SlotRef) && !(realItem instanceof FunctionCallExpr)
-                    && !(realItem instanceof ArithmeticExpr)) {
+            if (!(selectListItemExpr instanceof SlotRef) && !(selectListItemExpr instanceof FunctionCallExpr)
+                    && !(selectListItemExpr instanceof ArithmeticExpr)) {
                 throw new AnalysisException("The materialized view only support the single column or function expr. "
                         + "Error column: " + selectListItemExpr.toSql());
             }