Unexpected behavior in apollo service check with service name set in apollo.config.js

**Intended outcome:**

Given that you can set the service name and endpoint in `apollo.config` below

https://github.com/apollographql/apollo-tooling/blob/9ffe78d8b8c29282e2ea59d6edd5451232341ed8/packages/apollo-language-server/src/config/config.ts#L131-L135

https://github.com/apollographql/apollo-tooling/blob/9ffe78d8b8c29282e2ea59d6edd5451232341ed8/packages/apollo-language-server/src/config/config.ts#L108-L112

I would expect [`apollo service:check`](https://github.com/apollographql/apollo-tooling#apollo-servicecheck) or `apollo service:push` to use these variables (specifically service name and endpoint) set in the config. Especially treating the service name in the config to be the same as the setting the `serviceName` flag i.e. it provides the name of the implementing service for a federated graph and indicates that the schema is a partial schema from a federated service

**Actual outcome:**

```
> yarn apollo service:check --serviceName='serviceA' --endpoint='http://localhost:3000/graphql'
✔ Loading Apollo Project
✔ Found 0 graph composition errors for service serviceA on graph SomeGraphName@current
```
is not equivalent to
```
> yarn apollo service:check -c apollo.config.js
✔ Loading Apollo Project
✔ Validating schema against metrics from variant current on graph SomeGraphName@current
```
where `apollo.config.js` contains
```
module.exports = {
service: {
name: 'serviceA',
endpoint: {
url: 'http://localhost:3000/graphql',
},
}
};
```

It appears the service commands do not parse service name from the `apollo.config` at all and only uses the value set in flags
https://github.com/apollographql/apollo-tooling/blob/ba640f68fd6f45bab0b628bbcc236ebfbb23eee8/packages/apollo/src/commands/service/check.ts#L334

**How to reproduce the issue:**
See above for an example

**Versions**

apollo/2.27.3 darwin-x64 node-v12.14.0

Start with the service configuration fields in packages/apollo-language-server/src/config/config.ts and the service command logic in packages/apollo/src/commands/service/check.ts, then reproduce the two commands described in the issue. Done means service:check and service:push honor the configured service name and endpoint consistently with the corresponding flags.

Written by the indexing model from the issue text.