fix: fix helm install failed when enable ingress

deploy/charts/emqx/templates/ingress.yaml

@@ -27,9 +27,9 @@ spec:
   - host: {{ $host }}
     http:
       paths:
-      - path: /
+      - path: {{ $.Values.ingress.dashboard.path | default "/" }}
         {{- if (semverCompare ">=1.18-0" $.Capabilities.KubeVersion.GitVersion) }}
-        pathType: {{ .Values.ingress.dashboard.pathType | default "ImplementationSpecific" }}
+        pathType: {{ $.Values.ingress.dashboard.pathType | default "ImplementationSpecific" }}
         {{- end }}
         backend:
           {{- if semverCompare ">=1.19-0" $.Capabilities.KubeVersion.GitVersion }}