feat(admin-character): 캐릭터 배너 리스트 API

- 배너 이미지 URL - hostimagePath => host/imagePath로 수정

src/main/kotlin/kr/co/vividnext/sodalive/admin/chat/dto/ChatCharacterBannerResponse.kt

@@ -15,7 +15,7 @@ data class ChatCharacterBannerResponse(
         fun from(banner: ChatCharacterBanner, imageHost: String): ChatCharacterBannerResponse {
             return ChatCharacterBannerResponse(
                 id = banner.id!!,
-                imagePath = "$imageHost${banner.imagePath}",
+                imagePath = "$imageHost/${banner.imagePath}",
                 characterId = banner.chatCharacter.id!!,
                 characterName = banner.chatCharacter.name
             )