[FIX] web: add the missing views in legacy_views

Before this commit, the switch from a multiple view (list, kanban, ...)
to a custom form view was not correctly done. The form view displayed
was not the custom version but the default one.

This problem is caused by the filter applied on viewSwitcherEntries
which removes the form views because they are not a multiple view.

To solve this problem, we will add the missing form view in the
actions.views given to the legacy view.

closes odoo-dev/odoo#958

Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>

addons/web/static/src/legacy/legacy_views.js

@@ -101,10 +101,24 @@ function registerView(name, LegacyView) {
                     viewFields: result.fields_views.search.fields,
                 });
             }
+            const views = this.viewParams.action.views
+                .filter(([vid, vtype]) => vtype !== "search")
+                .map(([vid, vtype]) => {
+                    const view = this.props.viewSwitcherEntries.find((v) => v.type === vtype);
+                    if (view) {
+                        return Object.assign({}, view, {viewID: vid});
+                    } else {
+                        return {
+                            viewID: vid,
+                            type: vtype,
+                            multiRecord: !this.constructor.multiRecord,
+                        };
+                    }
+                });
             this.viewParams.action = Object.assign({}, this.viewParams.action, {
                 controlPanelFieldsView,
                 _views: this.viewParams.action.views,
-                views: this.props.viewSwitcherEntries,
+                views,
             });
         }
     }