fix(go/adbc/driver/flightsql): Parsing column metadata in FlightSQL d…

…river (#2481)

* Fixes [#2434](#2434)
* Moved driver-agnostic metadata parsing out of `shared_utils.go`
* Each driver can now implement its own logic for handling `XDBC_`
fields using fields metadata
* Snowflake and BigQuery drivers seem unaffected as they use separate
implementations
* Relocated `ToXdbcDataType` function to `shared_utils.go` to resolve
circular dependency issues
* Aligned implementation with documentation by:
  * Ensuring all documented XDBC_ fields are properly fetched
* Removing undocumented fields (`COMMENT`, `CHARACTER_MAXIMUM_LENGTH`,
`XDBC_SCALE`, `XDBC_PRECISION`)
*`COMMENT`, `CHARACTER_MAXIMUM_LENGTH` seem to be snowflake specific
even though it seems snowflake adbc driver has a separate
implementation.
* Couldn't find any documentation regarding `XDBC_SCALE`,
`XDBC_PRECISION`
* Restored tests that verify proper metadata field population

go/adbc/driver/bigquery/connection.go

@@ -208,7 +208,7 @@ func (c *connectionImpl) GetTablesForDBSchema(ctx context.Context, catalog strin
 					if err != nil {
 						return nil, err
 					}
-					xdbcDataType := driverbase.ToXdbcDataType(field.Type)
+					xdbcDataType := internal.ToXdbcDataType(field.Type)
 
 					columns = append(columns, driverbase.ColumnInfo{
 						ColumnName:          fieldschema.Name,