fix(pro:textarea): row number is `0` when value is undefined

[sallerli1]

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] The commit message follows our guidelines
• [x] Tests for the changes have been added/updated or not needed
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What is the current behavior?

当初始的value是undefined的时候，第一行的行号是0

What is the new behavior?

修复以上问题，第一行的行号始终是1

Other information

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 90.88%. Comparing base (a8515bb) to head (9bf35ea).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1979 +/- ## ======================================= Coverage 90.88% 90.88% ======================================= Files 358 358 Lines 35824 35824 Branches 3901 3901 ======================================= Hits 32558 32558 Misses 3266 3266 ```

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