Configure the identity's controller proxy to discovery policies (#6873)

Now that the proxy uses its default policy at startup and can discover
its policies lazily, the identity controller no longer must be exempt
from policy discovery. This enables the identity controller to enforce
admin server policies, in particular.

This change enables policy discovery on the identity controller.

Author: olix0r

charts/partials/templates/_proxy.tpl

@@ -33,7 +33,6 @@ env:
   value: {{ternary "localhost.:8086" (printf "linkerd-dst-headless.%s.svc.%s.:8086" .Values.namespace .Values.clusterDomain) (eq (toString .Values.proxy.component) "linkerd-destination")}}
 - name: LINKERD2_PROXY_DESTINATION_PROFILE_NETWORKS
   value: {{.Values.clusterNetworks | quote}}
-{{ if (ne (toString .Values.proxy.component) "linkerd-identity") -}}
 - name: LINKERD2_PROXY_POLICY_SVC_ADDR
   value: {{ternary "localhost.:8090" (printf "linkerd-policy.%s.svc.%s.:8090" .Values.namespace .Values.clusterDomain) (eq (toString .Values.proxy.component) "linkerd-destination")}}
 - name: LINKERD2_PROXY_POLICY_WORKLOAD
@@ -42,7 +41,6 @@ env:
   value: {{.Values.proxy.defaultInboundPolicy | default .Values.policyController.defaultAllowPolicy}}
 - name: LINKERD2_PROXY_POLICY_CLUSTER_NETWORKS
   value: {{.Values.clusterNetworks | quote}}
-{{ end -}}
 {{ if .Values.proxy.inboundConnectTimeout -}}
 - name: LINKERD2_PROXY_INBOUND_CONNECT_TIMEOUT
   value: {{.Values.proxy.inboundConnectTimeout | quote}}
@@ -128,11 +126,9 @@ be used in other contexts.
   value: linkerd-identity.{{.Values.namespace}}.serviceaccount.identity.{{.Values.namespace}}.{{$trustDomain}}
 - name: LINKERD2_PROXY_DESTINATION_SVC_NAME
   value: linkerd-destination.{{.Values.namespace}}.serviceaccount.identity.{{.Values.namespace}}.{{$trustDomain}}
-{{ if (ne (toString .Values.proxy.component) "linkerd-identity") -}}
 - name: LINKERD2_PROXY_POLICY_SVC_NAME
   value: linkerd-destination.{{.Values.namespace}}.serviceaccount.identity.{{.Values.namespace}}.{{$trustDomain}}
 {{ end -}}
-{{ end -}}
 image: {{.Values.proxy.image.name}}:{{.Values.proxy.image.version | default .Values.linkerdVersion}}
 imagePullPolicy: {{.Values.proxy.image.pullPolicy | default .Values.imagePullPolicy}}
 livenessProbe: