refactor(drivers): 更新数据插入操作中的集合类型定义

- 将 dm 驱动中的 conflictKeySet 从 gset.New 修改为 gset.NewStrSet
- 将 gaussdb 驱动中的 conflictKeySet 从 gset.New 修改为 gset.NewStrSet
- 将 mssql 驱动中的 conflictKeySet 从 gset.New 修改为 gset.NewStrSet
- 将 oracle 驱动中的 conflictKeySet 从 gset.New 修改为 gset.NewStrSet
- 统一使用字符串集合类型以提高类型安全性

contrib/drivers/dm/dm_do_insert.go

@@ -108,7 +108,7 @@ func (d *Driver) doMergeInsert(
 		one            = list[0]
 		oneLen         = len(one)
 		charL, charR   = d.GetChars()
-		conflictKeySet = gset.New(false)
+		conflictKeySet = gset.NewStrSet(false)
 
 		// queryHolders:	Handle data with Holder that need to be merged
 		// queryValues:		Handle data that need to be merged

contrib/drivers/gaussdb/gaussdb_do_insert.go

@@ -307,7 +307,7 @@ func (d *Driver) doMergeInsert(
 		one            = list[0]
 		oneLen         = len(one)
 		charL, charR   = d.GetChars()
-		conflictKeySet = gset.New(false)
+		conflictKeySet = gset.NewStrSet(false)
 
 		// queryHolders:	Handle data with Holder that need to be merged
 		// queryValues:		Handle data that need to be merged

contrib/drivers/mssql/mssql_do_insert.go

@@ -102,7 +102,7 @@ func (d *Driver) doMergeInsert(
 		one            = list[0]
 		oneLen         = len(one)
 		charL, charR   = d.GetChars()
-		conflictKeySet = gset.New(false)
+		conflictKeySet = gset.NewStrSet(false)
 
 		// queryHolders:	Handle data with Holder that need to be merged
 		// queryValues:		Handle data that need to be merged

contrib/drivers/oracle/oracle_do_insert.go

@@ -181,7 +181,7 @@ func (d *Driver) doMergeInsert(
 		one            = list[0]
 		oneLen         = len(one)
 		charL, charR   = d.GetChars()
-		conflictKeySet = gset.New(false)
+		conflictKeySet = gset.NewStrSet(false)
 
 		// queryHolders:	Handle data with Holder that need to be upsert
 		// queryValues:		Handle data that need to be upsert