fix(comment-nickname): deleted_ 로 시작하는 닉네임 접두사 노출을 제거한다

src/main/kotlin/kr/co/vividnext/sodalive/extensions/StringExtensions.kt

@@ -5,6 +5,8 @@ import java.time.LocalDateTime
 import java.time.ZoneId
 import java.time.format.DateTimeFormatter
 
+private const val DELETED_NICKNAME_PREFIX = "deleted_"
+
 fun String.convertLocalDateTime(format: String): LocalDateTime {
     val dateTimeFormatter = DateTimeFormatter.ofPattern(format)
     return LocalDateTime.parse(this, dateTimeFormatter)
@@ -24,3 +26,11 @@ fun String.convertLocalDateTime(
         .withZoneSameInstant(ZoneId.of("UTC"))
         .toLocalDateTime()
 }
+
+fun String.removeDeletedNicknamePrefix(): String {
+    return if (startsWith(DELETED_NICKNAME_PREFIX)) {
+        removePrefix(DELETED_NICKNAME_PREFIX)
+    } else {
+        this
+    }
+}