[FIX] stock: fix empty forecasted report.

When there was no data, the graph overlaps
the empty table. Remove force height in css.

X-original-commit: 8a73dc77

addons/stock/static/src/scss/report_stock_forecasted.scss

@@ -8,8 +8,4 @@
     .o_forecasted_row {
         background-color: #dee2e6;
     }
-
-    .o_report_graph {
-        height: 300px;
-    }
 }