refactor: use the built-in max/min to simplify the code (#17059)

### Summary

In Go 1.21, the standard library includes built-in
[max/min](https://pkg.go.dev/builtin@go1.21.0#max) function, which can
greatly simplify the code.

Signed-off-by: futurehua <futurehua@outlook.com>

internal/engine/infinity/chunk.go

@@ -703,10 +703,7 @@ func (e *infinityEngine) Search(ctx context.Context, req *types.SearchRequest) (
 		pageSize = 30
 	}
 
-	offset := req.Offset
-	if offset < 0 {
-		offset = 0
-	}
+	offset := max(req.Offset, 0)
 
 	db, release, err := e.client.checkoutDatabase(ctx, "chunk.go")
 	if err != nil {

internal/engine/infinity/metadata.go

@@ -583,10 +583,7 @@ func (e *infinityEngine) SearchMetadata(ctx context.Context, req *types.SearchMe
 	if pageSize <= 0 {
 		pageSize = 30
 	}
-	offset := req.Offset
-	if offset < 0 {
-		offset = 0
-	}
+	offset := max(req.Offset, 0)
 
 	// Build filter from req.Filter
 	var filterStr string