Empty fields being including despite field mask

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### A screenshot that you have tested with "Try this API".
EDIT BY MAINTAINER (confirmed field masks work with try the API - used user's requests and specified addressComponents in the `fields` section on Try the API)

The field mask (`X-Goog-FieldMask`) is adhering to setting the fields returned by the functions, e.g. i didn't specify `rating` therefore it is 0.

However shouldn't the empty fields be not returned as part of the function call, e.g. `searchNearby`.

This requires manual intervention and processing to remove these unset fields.

A side question.. Where are the default values here set?

```
const fieldMask = 'places.displayName,places.addressComponents';
const request = {
includedTypes: ['coffee_shop'],
maxResultCount: 10,
regionCode: 'GB',
languageCode: 'en-GB',
rankPreference: google.maps.places.v1.SearchNearbyRequest.RankPreference.POPULARITY,
locationRestriction: {
circle: {
center: {
latitude: 50.232671229974386,
longitude: -3.765861197206113
},
radius: 1000.0
}
}
};
const callOptions = {
//autoPaginate: false,
otherArgs: {
headers: {
'X-Goog-FieldMask': fieldMask,
},
},
};
const [ resultArray, nextPageRequest, rawRespone ] = await this.#placesClient.searchNearby(request, callOptions);
console.log('searchNearby', resultArray);
```

Output includes fields not specifically requested in the field mask:

```
...
attributions: [],
currentSecondaryOpeningHours: [],
regularSecondaryOpeningHours: [],
reviews: [],
photos: [],
subDestinations: [],
containingPlaces: [],
name: '',
id: 'ChIJ9T5tCwXfbEgR8k2EaHtBkB',
nationalPhoneNumber: '',
internationalPhoneNumber: '',
formattedAddress: '',
plusCode: null,
location: null,
viewport: null,
rating: 0,
googleMapsUri: '',
websiteUri: '',
regularOpeningHours: null,
adrFormatAddress: '',
businessStatus: 'BUSINESS_STATUS_UNSPECIFIED',
priceLevel: 'PRICE_LEVEL_UNSPECIFIED',
iconMaskBaseUri: '',
...
```

### Link to the code that reproduces this issue. A link to a **public** Github Repository or gist with a minimal reproduction.

https://gist.github.com/mstephens/d3224c292e4b242e2dee38bb3bf31864

### A step-by-step description of how to reproduce the issue, based on the linked reproduction.

1. Run function `searchNearby`

### A clear and concise description of what the bug is, and what you expected to happen.

Fields not specified in field mask, to not be returned

### A clear and concise description WHY you expect this behavior, i.e., was it a recent change, there is documentation that points to this behavior, etc. **

In the same way in which the 'vanilla' `https://places.googleapis.com/v1/places:searchNearby` API operates