Change capitalisation of token header

This fixes all the test failures seen here apart from the
job adapter ones:
https://app.circleci.com/pipelines/github/hashicorp/nomad/14501/workflows/01177cd9-a2ae-4fff-94ef-6b109b778123/jobs/134238

This was last toggled in #8035 and it’s frustrating to have
to change it back but I couldn’t find another way 😞

ui/mirage/config.js

@@ -352,7 +352,7 @@ export default function() {
   });
 
   this.get('/acl/token/self', function({ tokens }, req) {
-    const secret = req.requestHeaders['x-nomad-token'];
+    const secret = req.requestHeaders['X-Nomad-Token'];
     const tokenForSecret = tokens.findBy({ secretId: secret });
 
     // Return the token if it exists
@@ -366,7 +366,7 @@ export default function() {
 
   this.get('/acl/token/:id', function({ tokens }, req) {
     const token = tokens.find(req.params.id);
-    const secret = req.requestHeaders['x-nomad-token'];
+    const secret = req.requestHeaders['X-Nomad-Token'];
     const tokenForSecret = tokens.findBy({ secretId: secret });
 
     // Return the token only if the request header matches the token
@@ -381,7 +381,7 @@ export default function() {
 
   this.get('/acl/policy/:id', function({ policies, tokens }, req) {
     const policy = policies.find(req.params.id);
-    const secret = req.requestHeaders['x-nomad-token'];
+    const secret = req.requestHeaders['X-Nomad-Token'];
     const tokenForSecret = tokens.findBy({ secretId: secret });
 
     if (req.params.id === 'anonymous') {

ui/tests/unit/adapters/job-test.js

@@ -133,7 +133,7 @@ module('Unit | Adapter | Job', function(hooks) {
     );
   });
 
-  test('When there is no token set in the token service, no x-nomad-token header is set', async function(assert) {
+  test('When there is no token set in the token service, no X-Nomad-Token header is set', async function(assert) {
     await this.initializeUI();
 
     const { pretender } = this.server;
@@ -143,12 +143,12 @@ module('Unit | Adapter | Job', function(hooks) {
     await settled();
 
     assert.notOk(
-      pretender.handledRequests.mapBy('requestHeaders').some(headers => headers['x-nomad-token']),
+      pretender.handledRequests.mapBy('requestHeaders').some(headers => headers['X-Nomad-Token']),
       'No token header present on either job request'
     );
   });
 
-  test('When a token is set in the token service, then x-nomad-token header is set', async function(assert) {
+  test('When a token is set in the token service, then X-Nomad-Token header is set', async function(assert) {
     await this.initializeUI();
 
     const { pretender } = this.server;
@@ -162,7 +162,7 @@ module('Unit | Adapter | Job', function(hooks) {
     assert.ok(
       pretender.handledRequests
         .mapBy('requestHeaders')
-        .every(headers => headers['x-nomad-token'] === secret),
+        .every(headers => headers['X-Nomad-Token'] === secret),
       'The token header is present on both job requests'
     );
   });