refactor(ranking): CDN URL 변환 공통 함수를 사용한다

src/main/kotlin/kr/co/vividnext/sodalive/v2/ranking/application/CreatorRankingQueryService.kt

@@ -1,5 +1,6 @@
 package kr.co.vividnext.sodalive.v2.ranking.application
 
+import kr.co.vividnext.sodalive.v2.common.domain.toCdnUrl
 import kr.co.vividnext.sodalive.v2.ranking.domain.CreatorRankingItem
 import kr.co.vividnext.sodalive.v2.ranking.domain.CreatorRankingPeriodPolicy
 import kr.co.vividnext.sodalive.v2.ranking.domain.CreatorRankingScorePolicy
@@ -159,14 +160,10 @@ class CreatorRankingQueryService(
             isNew = false,
             creatorId = creatorId,
             nickname = nickname,
-            profileImageUrl = profileImageUrl.toCdnUrl()
+            profileImageUrl = profileImageUrl.toCdnUrl(cloudFrontHost)
         )
     }
 
-    private fun String?.toCdnUrl(): String? {
-        return if (isNullOrBlank()) null else "$cloudFrontHost/$this"
-    }
-
     private fun CreatorRankingSnapshotCandidate.toSnapshotRecord(utcRange: CreatorRankingUtcRange): CreatorRankingSnapshotRecord {
         val calculatedContentLiveScore = scorePolicy.calculateContentLiveScore(
             liveCanAmount = liveCanAmount,