SQL Expressions: Add STDDEV(), VARIANCE() and aliases (#103851)

* SQL Expressions: Bump GMS for STDDEV(), VARIANCE()

Bump Go MySQL Server to the latest version, to get support for STDDEV()
and VARIANCE() functions, and their aliases.

See https://github.com/dolthub/go-mysql-server/pull/2928

* Update app-code to comply with latest GMS version

* Run `go mod tidy`

* Update test which had depended on STDDEV being missing

* Run `make update-workspace`

pkg/expr/sql/frame_db_conv.go

@@ -42,7 +42,7 @@ func convertToDataFrame(ctx *mysql.Context, iter mysql.RowIter, schema mysql.Sch
 		for i, val := range row {
 			// Run val through mysql.Type.Convert to normalize underlying value
 			// of the interface
-			nV, _, err := schema[i].Type.Convert(val)
+			nV, _, err := schema[i].Type.Convert(ctx, val)
 			if err != nil {
 				return nil, err
 			}