Fix redundant 'MB' string in zh/ko translation of downloading file dialog.

As crbug.com/985803 described, there is redundant 'MB' string in Chinese/Korean
translations of downloading file dialog.

Bug: 985803
Change-Id: I66a254494d749018b33d10896055bf1edeff6bcb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1710081Reviewed-by: Mustafa Emre Acer <meacer@chromium.org>
Reviewed-by: Krishna Govind <govind@chromium.org>
Commit-Queue: Krishna Govind <govind@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681376}

chrome/android/java/strings/translations/android_chrome_strings_ko.xtb

@@ -527,7 +527,7 @@
 <translation id="4962975101802056554">기기에서 모든 권한을 취소합니다.</translation>
 <translation id="4970824347203572753">현재 위치에서 사용할 수 없습니다.</translation>
 <translation id="497421865427891073">앞으로 이동</translation>
-<translation id="4988210275050210843">파일 다운로드 중(<ph name="MEGABYTES" />MB)</translation>
+<translation id="4988210275050210843">파일 다운로드 중(<ph name="MEGABYTES" />)</translation>
 <translation id="4988526792673242964">페이지</translation>
 <translation id="4994033804516042629">연락처 없음</translation>
 <translation id="4996978546172906250">공유 방법</translation>

chrome/android/java/strings/translations/android_chrome_strings_zh-CN.xtb

@@ -527,7 +527,7 @@
 <translation id="4962975101802056554">撤消设备的所有权限</translation>
 <translation id="4970824347203572753">无法在您所在的国家/地区使用</translation>
 <translation id="497421865427891073">前进</translation>
-<translation id="4988210275050210843">正在下载文件（<ph name="MEGABYTES" /> MB）。</translation>
+<translation id="4988210275050210843">正在下载文件（<ph name="MEGABYTES" />）。</translation>
 <translation id="4988526792673242964">网页</translation>
 <translation id="4994033804516042629">找不到任何联系人</translation>
 <translation id="4996978546172906250">分享方式</translation>

chrome/android/java/strings/translations/android_chrome_strings_zh-TW.xtb

@@ -527,7 +527,7 @@
 <translation id="4962975101802056554">撤銷裝置的所有權限</translation>
 <translation id="4970824347203572753">你所在的地區無法使用這項功能</translation>
 <translation id="497421865427891073">往前</translation>
-<translation id="4988210275050210843">正在下載檔案 (<ph name="MEGABYTES" /> MB)。</translation>
+<translation id="4988210275050210843">正在下載檔案 (<ph name="MEGABYTES" />)。</translation>
 <translation id="4988526792673242964">網頁</translation>
 <translation id="4994033804516042629">找不到任何聯絡人</translation>
 <translation id="4996978546172906250">分享方式：</translation>