helm: add `/config` proxy_pass to nginx gateway (#10000)

### issue:
According to the issue https://github.com/grafana/loki/issues/9917
Adding Grafana Loki Enterprise to Grafana Apps Enterprise needs access
to the GEL `/config` API path for cluster configuration

if GEL Apps in Grafana doesn't have an access to this path, client won't
be able to see `/Cluster Configuration` and also won't be able to create
a data source in the Apps with the related Grafana Enterprise logs
plugin.

### more information: 

`HOME/Apps/Grfana Enterprise Logs/Cluster Configuration`

```
A note about this cluster configuration page

The parameter values shown below are those returned by http://example.com:30519/config. If you have configured other components in your cluster with different parameter values, those will not be reflected below.

For documentation on the function of each configuration parameter, see [Configuration reference](https://grafana.com/docs/enterprise-logs/latest/config/reference/).
```
<img width="712" alt="Screenshot 1402-04-30 at 03 17 34"
src="https://github.com/grafana/loki/assets/53074289/48170dce-345d-42d8-bbaa-1bdf4d7bd2f3">



This commit will add `/config` to nginx gateway on SSD mode loki helm
chart deployment

---------

Signed-off-by: Michel Hollands <michel.hollands@gmail.com>
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: Michel Hollands <42814411+MichelHollands@users.noreply.github.com>
Co-authored-by: Joao Marcal <jmarcal@redhat.com>
Co-authored-by: Periklis Tsirakidis <periklis@redhat.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Salva Corts <salva.corts@grafana.com>

production/helm/loki/CHANGELOG.md

@@ -13,6 +13,10 @@ Entries should include a reference to the pull request that introduced the chang
 
 [//]: # (<AUTOMATED_UPDATES_LOCATOR> : do not remove this line. This locator is used by the CI pipeline to automatically create a changelog entry for each new Loki release. Add other chart versions and respective changelog entries bellow this line.)
 
+## 5.8.11
+
+- [BUGFIX] Fix gateway: Add `/config` proxy_pass to nginx configuration
+
 ## 5.8.10
 
 - [ENHANCEMENT] Canary labelname can now be configured via monitoring.lokiCanary.labelname

production/helm/loki/Chart.yaml

@@ -3,7 +3,7 @@ name: loki
 description: Helm chart for Grafana Loki in simple, scalable mode
 type: application
 appVersion: 2.8.2
-version: 5.8.10
+version: 5.8.11
 home: https://grafana.github.io/helm-charts
 sources:
   - https://github.com/grafana/loki

production/helm/loki/README.md

@@ -1,6 +1,6 @@
 # loki
 
-![Version: 5.8.10](https://img.shields.io/badge/Version-5.8.10-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 2.8.2](https://img.shields.io/badge/AppVersion-2.8.2-informational?style=flat-square)
+![Version: 5.8.11](https://img.shields.io/badge/Version-5.8.11-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 2.8.2](https://img.shields.io/badge/AppVersion-2.8.2-informational?style=flat-square)
 
 Helm chart for Grafana Loki in simple, scalable mode
 

production/helm/loki/templates/_helpers.tpl

@@ -724,6 +724,11 @@ http {
       proxy_pass       {{ $backendUrl }}$request_uri;
     }
 
+    # Config
+    location = /config {
+      proxy_pass       {{ $backendUrl }}$request_uri;
+    }
+    
     {{- if and .Values.enterprise.enabled .Values.enterprise.adminApi.enabled }}
     # Admin API
     location ^~ /admin/api/ {