Database Rules Deploy ignores instance

### [REQUIRED] Environment info

**firebase-tools:** 9.2.0

**Platform:** macOs

### [REQUIRED] Test case

I have a project, `fir-dumpster` with three databases:

* https://fir-dumpster.firebaseio.com/ (default)
* https://fir-dumpster-europe.europe-west1.firebasedatabase.app/
* https://fir-dumpster-secondary.firebaseio.com/
firebase.json
```
{
"database": {
"rules": "database.rules.json"
}
}
```

### [REQUIRED] Steps to reproduce

Try to deploy rules to the second instance using this command:
```
firebase --debug deploy --only database:fir-dumpster-europe
```

### [REQUIRED] Expected behavior

Update the rules of `fir-dumpster-europe.europe-west1.firebasedatabase.app`

### [REQUIRED] Actual behavior

Deploys to the default instance, see logs below:

```
$ firebase --debug deploy --only database:fir-dumpster-europe
[2021-01-29T11:55:08.788Z] > command requires scopes: ["email","openid","https://www.googleapis.com/auth/cloudplatformprojects.readonly","https://www.googleapis.com/auth/firebase","https://www.googleapis.com/auth/cloud-platform"]
[2021-01-29T11:55:08.790Z] > authorizing via signed-in user
[2021-01-29T11:55:08.790Z] [iam] checking project fir-dumpster for permissions ["firebase.projects.get","firebasedatabase.instances.update"]
[2021-01-29T11:55:08.793Z] >>> HTTP REQUEST POST https://cloudresourcemanager.googleapis.com/v1/projects/fir-dumpster:testIamPermissions
{"permissions":["firebase.projects.get","firebasedatabase.instances.update"]}
[2021-01-29T11:55:18.361Z] [iam] error while checking permissions, command may fail: FirebaseError: Server Error. Client network socket disconnected before secure TLS connection was established
[2021-01-29T11:55:18.363Z] > refreshing access token with scopes: []
[2021-01-29T11:55:18.363Z] >>> HTTP REQUEST POST https://www.googleapis.com/oauth2/v3/token

[2021-01-29T11:55:18.635Z] <<< HTTP RESPONSE 200 {"date":"Fri, 29 Jan 2021 11:55:18 GMT","cache-control":"no-cache, no-store, max-age=0, must-revalidate","expires":"Mon, 01 Jan 1990 00:00:00 GMT","pragma":"no-cache","content-type":"application/json; charset=utf-8","vary":"X-Origin, Referer, Origin,Accept-Encoding","server":"scaffolding on HTTPServer2","x-xss-protection":"0","x-frame-options":"SAMEORIGIN","x-content-type-options":"nosniff","alt-svc":"h3-29=\":443\"; ma=2592000,h3-T051=\":443\"; ma=2592000,h3-Q050=\":443\"; ma=2592000,h3-Q046=\":443\"; ma=2592000,h3-Q043=\":443\"; ma=2592000,quic=\":443\"; ma=2592000; v=\"46,43\"","accept-ranges":"none","transfer-encoding":"chunked"}
[2021-01-29T11:55:18.680Z] >>> [apiv2][query] GET https://firebase.googleapis.com/v1beta1/projects/fir-dumpster [none]
[2021-01-29T11:55:19.029Z] <<< [apiv2][status] GET https://firebase.googleapis.com/v1beta1/projects/fir-dumpster 200
[2021-01-29T11:55:19.029Z] <<< [apiv2][body] GET https://firebase.googleapis.com/v1beta1/projects/fir-dumpster {"projectId":"fir-dumpster","projectNumber":"733471010301","displayName":"FirebaseDumpster","name":"projects/fir-dumpster","resources":{"hostingSite":"fir-dumpster","realtimeDatabaseInstance":"fir-dumpster","storageBucket":"fir-dumpster.appspot.com","locationId":"us-central"},"state":"ACTIVE"}

=== Deploying to 'fir-dumpster'...

i deploying database
i database: checking rules syntax...
[2021-01-29T11:55:19.033Z] > refreshing access token with scopes: ["email","https://www.googleapis.com/auth/cloud-platform","https://www.googleapis.com/auth/cloudplatformprojects.readonly","https://www.googleapis.com/auth/firebase","openid"]
[2021-01-29T11:55:19.033Z] >>> HTTP REQUEST POST https://www.googleapis.com/oauth2/v3/token

[2021-01-29T11:55:19.307Z] <<< HTTP RESPONSE 200 {"cache-control":"no-cache, no-store, max-age=0, must-revalidate","date":"Fri, 29 Jan 2021 11:55:19 GMT","pragma":"no-cache","expires":"Mon, 01 Jan 1990 00:00:00 GMT","content-type":"application/json; charset=utf-8","vary":"X-Origin, Referer, Origin,Accept-Encoding","server":"scaffolding on HTTPServer2","x-xss-protection":"0","x-frame-options":"SAMEORIGIN","x-content-type-options":"nosniff","alt-svc":"h3-29=\":443\"; ma=2592000,h3-T051=\":443\"; ma=2592000,h3-Q050=\":443\"; ma=2592000,h3-Q046=\":443\"; ma=2592000,h3-Q043=\":443\"; ma=2592000,quic=\":443\"; ma=2592000; v=\"46,43\"","accept-ranges":"none","transfer-encoding":"chunked"}
[2021-01-29T11:55:19.342Z] >>> HTTP REQUEST GET https://firebasedatabase.googleapis.com/v1beta/projects/fir-dumpster/locations/-/instances/fir-dumpster

[2021-01-29T11:55:19.808Z] <<< HTTP RESPONSE 200 {"content-type":"application/json; charset=UTF-8","vary":"X-Origin, Referer, Origin,Accept-Encoding","date":"Fri, 29 Jan 2021 11:55:19 GMT","server":"ESF","cache-control":"private","x-xss-protection":"0","x-frame-options":"SAMEORIGIN","x-content-type-options":"nosniff","alt-svc":"h3-29=\":443\"; ma=2592000,h3-T051=\":443\"; ma=2592000,h3-Q050=\":443\"; ma=2592000,h3-Q046=\":443\"; ma=2592000,h3-Q043=\":443\"; ma=2592000,quic=\":443\"; ma=2592000; v=\"46,43\"","accept-ranges":"none","transfer-encoding":"chunked"}
[2021-01-29T11:55:19.811Z] >>> HTTP REQUEST PUT https://fir-dumpster.firebaseio.com/.settings/rules.json?dryRun=true
{
"rules": {
".read": "true",
".write": "false",
"sub": {
".read": "true",
".write": "false"
}
}
}

[2021-01-29T11:55:21.666Z] <<< HTTP RESPONSE 200 {"server":"nginx","date":"Fri, 29 Jan 2021 11:55:21 GMT","content-type":"application/json; charset=utf-8","content-length":"15","connection":"keep-alive","access-control-allow-origin":"*","cache-control":"no-cache","strict-transport-security":"max-age=31556926; includeSubDomains; preload"}
✔ database: rules syntax for database fir-dumpster is valid
i database: releasing rules...
[2021-01-29T11:55:21.668Z] >>> HTTP REQUEST GET https://firebasedatabase.googleapis.com/v1beta/projects/fir-dumpster/locations/-/instances/fir-dumpster

[2021-01-29T11:55:22.119Z] <<< HTTP RESPONSE 200 {"content-type":"application/json; charset=UTF-8","vary":"X-Origin, Referer, Origin,Accept-Encoding","date":"Fri, 29 Jan 2021 11:55:22 GMT","server":"ESF","cache-control":"private","x-xss-protection":"0","x-frame-options":"SAMEORIGIN","x-content-type-options":"nosniff","alt-svc":"h3-29=\":443\"; ma=2592000,h3-T051=\":443\"; ma=2592000,h3-Q050=\":443\"; ma=2592000,h3-Q046=\":443\"; ma=2592000,h3-Q043=\":443\"; ma=2592000,quic=\":443\"; ma=2592000; v=\"46,43\"","accept-ranges":"none","transfer-encoding":"chunked"}
[2021-01-29T11:55:22.121Z] >>> HTTP REQUEST PUT https://fir-dumpster.firebaseio.com/.settings/rules.json
{
"rules": {
".read": "true",
".write": "false",
"sub": {
".read": "true",
".write": "false"
}
}
}

[2021-01-29T11:55:22.688Z] <<< HTTP RESPONSE 200 {"server":"nginx","date":"Fri, 29 Jan 2021 11:55:22 GMT","content-type":"application/json; charset=utf-8","content-length":"15","connection":"keep-alive","access-control-allow-origin":"*","cache-control":"no-cache","strict-transport-security":"max-age=31556926; includeSubDomains; preload"}
✔ database: rules for database fir-dumpster released successfully

✔ Deploy complete!

Project Console: https://console.firebase.google.com/project/fir-dumpster/overview
```