fix(graphql-request): Exporting GraphQLRequestModuleConfig interface

[vizio360]

Exporting GraphQLRequestModuleConfig interface to be able to use it when creating config classes like so:

...
imports: [
        ConfigModule.forFeature(corePdfClientConfig),
        GraphQLRequestModule.forRootAsync(GraphQLRequestModule, {
            useClass: CorePdfClientConfig,
            imports: [M2MAuthModule],
        }),
    ],

...

export class CorePdfClientConfig implements ModuleConfigFactory<GraphQLRequestModuleConfig> {