'currency' isn't a bidder-specific param

Update PR following this remark on another one:
prebid#3228 (comment)

Author: piotr-yuxuan

modules/adikteevBidAdapter.js

@@ -1,6 +1,7 @@
 import {registerBidder} from 'src/adapters/bidderFactory';
 import {BANNER} from 'src/mediaTypes';
 import * as utils from '../src/utils';
+import {config} from 'src/config';
 
 export const BIDDER_CODE = 'adikteev';
 export const ENDPOINT_URL = 'https://serve-adserver.adikteev.com/api/prebid/bid';
@@ -32,8 +33,6 @@ export const spec = {
     return !!(
       bid &&
       bid.params &&
-      bid.params.currency &&
-      bid.params.currency === 'EUR' &&
       bid.params.bidFloorPrice &&
       bid.params.placementId &&
       bid.bidder === BIDDER_CODE &&
@@ -45,7 +44,8 @@ export const spec = {
     const payload = {
       validBidRequests,
       bidderRequest,
-      referrerInfo: bidderRequest.refererInfo,
+      refererInfo: bidderRequest.refererInfo,
+      currency: config.getConfig('currency'),
       userAgent: navigator.userAgent,
       screen: {
         width: window.screen.width,

modules/adikteevBidAdapter.md

@@ -26,7 +26,6 @@ Module that connects to Adikteev's demand sources
                     bidder: 'adikteev',
                     params: {
                         placementId: 12345,
-                        currency: 'EUR',
                         bidFloorPrice: 0.1,
                     }
                 }

test/spec/modules/adikteevBidAdapter_spec.js

@@ -34,7 +34,6 @@ describe('adikteevBidAdapter', () => {
         bidder: 'adikteev',
         params: {
           placementId: 12345,
-          currency: 'EUR',
           bidFloorPrice: 0.1,
         },
         mediaTypes: {
@@ -62,7 +61,6 @@ describe('adikteevBidAdapter', () => {
         bidder: '', // invalid bidder
         params: {
           placementId: 12345,
-          currency: 'EUR',
           bidFloorPrice: 0.1,
         },
         mediaTypes: {
@@ -75,7 +73,6 @@ describe('adikteevBidAdapter', () => {
         bidder: 'adikteev',
         params: {
           placementId: '', // invalid placementId
-          currency: 'EUR',
           bidFloorPrice: 0.1,
         },
         mediaTypes: {
@@ -88,7 +85,6 @@ describe('adikteevBidAdapter', () => {
         bidder: 'adikteev',
         params: {
           placementId: 12345,
-          currency: 'EUR',
           bidFloorPrice: 0.1,
         },
         mediaTypes: {
@@ -121,6 +117,8 @@ describe('adikteevBidAdapter', () => {
         'screen',
         'language',
         'cookies',
+        // 'refererInfo',
+        // 'currency',
         'prebidUpdateVersion',
       );
       expect(requestData.validBidRequests).to.deep.equal(validBidRequests);