[Improvement-16754][DataX] Shorten batchSize placeholder text for better UI display

Shortened i18n placeholder from verbose text to concise version:
- zh_CN: "0 或留空为默认值 2048"
- en_US: "0 or empty = default 2048"

This prevents text truncation in the input field while maintaining core information.

Author: leocook

dolphinscheduler-ui/src/locales/en_US/project.ts

@@ -649,7 +649,7 @@ export default {
     datax_target_database_post_sql: 'Post SQL Statement',
     datax_non_query_sql_tips: 'Please enter the non-query sql statement',
     datax_writer_batch_size: 'Writer Batch Size',
-    datax_writer_batch_size_tips: '0 or empty means use DataX default (2048)',
+    datax_writer_batch_size_tips: '0 or empty = default 2048',
     datax_job_speed_byte: 'Speed(Byte count)',
     datax_job_speed_byte_info: '(0 means unlimited)',
     datax_job_speed_record: 'Speed(Record count)',

dolphinscheduler-ui/src/locales/zh_CN/project.ts

@@ -630,7 +630,7 @@ export default {
     datax_target_database_post_sql: '目标库后置SQL',
     datax_non_query_sql_tips: '请输入非查询SQL语句',
     datax_writer_batch_size: 'Writer 批量大小',
-    datax_writer_batch_size_tips: '0 或留空表示使用 DataX 默认值（2048）',
+    datax_writer_batch_size_tips: '0 或留空为默认值 2048',
     datax_job_speed_byte: '限流(字节数)',
     datax_job_speed_byte_info: '(KB，0代表不限制)',
     datax_job_speed_record: '限流(记录数)',