fix: prompt when parameter options are incompatible (#9247)

coderd/wsbuilder/wsbuilder.go

@@ -525,7 +525,7 @@ func (b *Builder) getParameters() (names, values []string, err error) {
 			// At this point, we've queried all the data we need from the database,
 			// so the only errors are problems with the request (missing data, failed
 			// validation, immutable parameters, etc.)
-			return nil, nil, BuildError{http.StatusBadRequest, err.Error(), err}
+			return nil, nil, BuildError{http.StatusBadRequest, fmt.Sprintf("Unable to validate parameter %q", templateVersionParameter.Name), err}
 		}
 		names = append(names, templateVersionParameter.Name)
 		values = append(values, value)