remove unused 'first' imports

src/app/+community-page/community-page.component.ts

-import { mergeMap, filter, map, first, tap } from 'rxjs/operators';
+import { mergeMap, filter, map } from 'rxjs/operators';
 import { ChangeDetectionStrategy, Component, OnDestroy, OnInit } from '@angular/core';
 import { ActivatedRoute } from '@angular/router';
 

src/app/+search-page/search-filters/search-filter/search-facet-filter/search-facet-filter.component.ts

@@ -6,7 +6,7 @@ import {
   Subject,
   Subscription
 } from 'rxjs';
-import { switchMap, distinctUntilChanged, first, map, take } from 'rxjs/operators';
+import { switchMap, distinctUntilChanged, map, take } from 'rxjs/operators';
 import { animate, state, style, transition, trigger } from '@angular/animations';
 import { Component, Inject, OnDestroy, OnInit } from '@angular/core';
 import { Router } from '@angular/router';

src/app/+search-page/search-filters/search-filter/search-filter.component.ts

 
-import { first, take } from 'rxjs/operators';
+import { take } from 'rxjs/operators';
 import { Component, Input, OnInit } from '@angular/core';
 import { SearchFilterConfig } from '../../search-service/search-filter-config.model';
 import { SearchFilterService } from './search-filter.service';

src/app/app.component.ts

-import { filter, first, map, take } from 'rxjs/operators';
+import { filter, map, take } from 'rxjs/operators';
 import {
   AfterViewInit,
   ChangeDetectionStrategy,

src/app/core/auth/auth.effects.ts

 import { of as observableOf, Observable } from 'rxjs';
 
-import { filter, debounceTime, switchMap, take, tap, catchError, map, first } from 'rxjs/operators';
+import { filter, debounceTime, switchMap, take, tap, catchError, map } from 'rxjs/operators';
 import { Injectable } from '@angular/core';
 
 // import @ngrx

src/app/core/auth/server-auth.service.ts

-import { first, map, switchMap, take } from 'rxjs/operators';
+import { map, switchMap, take } from 'rxjs/operators';
 import { Injectable } from '@angular/core';
 
 import { Observable } from 'rxjs';

src/app/core/cache/object-cache.service.ts

 import { combineLatest as observableCombineLatest, Observable } from 'rxjs';
 
-import { distinctUntilChanged, filter, first, map, mergeMap, take, } from 'rxjs/operators';
+import { distinctUntilChanged, filter, map, mergeMap, take, } from 'rxjs/operators';
 import { Injectable } from '@angular/core';
 import { MemoizedSelector, select, Store } from '@ngrx/store';
 import { IndexName } from '../index/index.reducer';

src/app/core/cache/server-sync-buffer.effects.ts

-import { delay, exhaustMap, first, map, switchMap, take, tap } from 'rxjs/operators';
+import { delay, exhaustMap, map, switchMap, take } from 'rxjs/operators';
 import { Inject, Injectable } from '@angular/core';
 import { Actions, Effect, ofType } from '@ngrx/effects';
 import {

src/app/core/shared/operators.ts

 import { Observable } from 'rxjs';
-import { filter, find, first, flatMap, map, tap } from 'rxjs/operators';
+import { filter, find, flatMap, map, tap } from 'rxjs/operators';
 import { hasValue, hasValueOperator, isNotEmpty } from '../../shared/empty.util';
 import { DSOSuccessResponse, RestResponse } from '../cache/response.models';
 import { RemoteData } from '../data/remote-data';

src/app/shared/host-window.service.ts

 import { combineLatest as observableCombineLatest, Observable } from 'rxjs';
 
-import { filter, distinctUntilChanged, map, first } from 'rxjs/operators';
+import { filter, distinctUntilChanged, map } from 'rxjs/operators';
 import { HostWindowState } from './host-window.reducer';
 import { Injectable } from '@angular/core';
 import { createSelector, select, Store } from '@ngrx/store';