`fetchIdToken` fails with a 400 error when using the `Compute` client on GKE with Workload Identity

#### Environment details
- OS: Alpine Linux v3.11
- Node.js version: v14.18.1
- npm version: 6.14.15
- `google-auth-library` version: 7.9.2

#### Steps to reproduce
1. Run a container in GKE with Workload Identity configured
2. Attempt to generate an ID token using the following code:

```js
const google = require('google-auth-library');
const client = await new google.GoogleAuth().getClient()
console.log(await client.fetchIdToken('IAP_CLIENT_ID'))

Uncaught:
GaxiosError: Could not fetch ID token: Unsuccessful response status code. Request failed with status code 400
at Gaxios._request (/app/node_modules/gaxios/build/src/gaxios.js:129:23)
at processTicksAndRejections (internal/process/task_queues.js:95:5)
at async metadataAccessor (/app/node_modules/gcp-metadata/build/src/index.js:68:21)
at async Compute.fetchIdToken (/app/node_modules/google-auth-library/build/src/auth/computeclient.js:80:23)
at async REPL4:1:36 {
response: {
config: {
url: 'http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/identity?format=full&[SNIP].apps.googleusercontent.com',
headers: [Object],
retryConfig: [Object],
responseType: 'text',
timeout: 3000,
paramsSerializer: [Function: paramsSerializer],
validateStatus: [Function: validateStatus],
method: 'GET'
},
data: 'non-empty audience parameter required\n',
headers: {
connection: 'close',
'content-length': '38',
'content-type': 'text/plain; charset=utf-8',
date: 'Tue, 19 Oct 2021 10:50:12 GMT',
'x-content-type-options': 'nosniff'
},
status: 400,
statusText: 'Bad Request',
request: {
responseURL: 'http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/identity?format=full&audience=[SNIP].apps.googleusercontent.com'
}
},
config: {
url: 'http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/identity?format=full&audience=[SNIP].apps.googleusercontent.com',
headers: { 'Metadata-Flavor': 'Google' },
retryConfig: {
noResponseRetries: 3,
currentRetryAttempt: 0,
retry: 3,
httpMethodsToRetry: [Array],
statusCodesToRetry: [Array]
},
responseType: 'text',
timeout: 3000,
paramsSerializer: [Function: paramsSerializer],
validateStatus: [Function: validateStatus],
method: 'GET'
},
code: '400'
}
```

#### Cause of issue
After some debugging what is going wrong it seems the Workload Identity Metadata server only accepts the `audience` query parameter if it is the first argument.

```sh
# Returns a valid token
$ wget -qO- --header="Metadata-Flavor: Google" http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/identity?audience=[snip].apps.googleusercontent.com&format=full
eyJhbGciOiJSUzI1NiIs[...snip...]

# Returns the same 400 error, note that only the order of the query params changed
$ wget -qO- --header="Metadata-Flavor: Google" http://169.254.169.254/computeMetadata/v1/instance/service-accounts/default/identity?format=full&audience=[snip].apps.googleusercontent.com
wget: server returned error: HTTP/1.1 400 Bad Request