Update charts/ext-proxy/templates/configmap.yaml

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: Ales Verbic <verbotenj@gmail.com>

Author: verbotenj

charts/ext-proxy/templates/configmap.yaml

@@ -19,7 +19,10 @@ data:
     {{- end }}
     {{- end }}
     {{- end }}
-{{- range $filename, $content := .Values.extraConfigs }}
-  {{ $filename }}: |
-{{ $content | indent 4 }}
+{{- if hasKey .Values.extraConfigs "tiers.toml" }}
+{{- fail "extraConfigs must not contain reserved key 'tiers.toml'" }}
+{{- end }}
+{{- range $filename := keys .Values.extraConfigs | sortAlpha }}
+  {{ $filename | quote }}: |
+{{ index $.Values.extraConfigs $filename | nindent 4 }}
 {{- end }}