Refactor frontend API URL generation in Helm chart

- Update the frontend.apiUrl helper function to directly use .Values.apiUrl, simplifying the logic for API URL configuration.
- This change enhances the flexibility of API URL settings by allowing direct user-defined values.

Author: PhiRho

helm/charts/frontend/templates/_helpers.tpl

@@ -55,9 +55,8 @@ Frontend-specific API URL generation.
 This provides a frontend-specific override if needed.
 */}}
 {{- define "frontend.apiUrl" -}}
-{{- $frontend := .Values.frontend | default dict -}}
-{{- if $frontend.apiUrl }}
-{{- $frontend.apiUrl | quote }}
+{{- if .Values.apiUrl }}
+{{- .Values.apiUrl | quote }}
 {{- else }}
 {{- $backendService := printf "%s-backend" .Release.Name }}
 {{- $port := "8800" }}