EntryJson interface has incorrect type for insertId

[interface EntryJson](https://github.com/googleapis/nodejs-logging/blob/a53b8f882452c2854d0b47bf92d2efdbada785dc/src/entry.ts#L70)
```typescript
export interface EntryJson {
timestamp: Timestamp;
insertId: number;
jsonPayload?: google.protobuf.IStruct;
textPayload?: string;
httpRequest?: google.logging.type.IHttpRequest;
trace?: string;
spanId?: string;
traceSampled?: boolean;
}
```

The property `insertId` has the incorrect type - it should be `string` as per https://cloud.google.com/logging/docs/reference/v2/rest/v2/LogEntry (and the other interfaces in the same file)

#### Environment details

- `@google-cloud/logging` version: 11.2