Set min value for history graph card rendered hours (#9464)

src/panels/lovelace/editor/config-elements/hui-history-graph-card-editor.ts

@@ -79,6 +79,7 @@ export class HuiHistoryGraphCardEditor
               "ui.panel.lovelace.editor.card.config.optional"
             )})"
             .value="${this._hours_to_show}"
+            min="1"
             .configValue=${"hours_to_show"}
             @value-changed="${this._valueChanged}"
           ></paper-input>