fix(@toss/validators): Reject 010 numbers that don’t have exactly 8 digits after the prefix

[chosanghyeon-dev]

Overview

• The previous KR mobile phone validator didn’t strictly check the length of the digits following 010, causing numbers like 0101234123 to be incorrectly treated as valid.
• Updated the regex so that 010 numbers are valid only when they contain exactly 8 digits after the prefix (i.e., total length of 11 digits).
• Added 0101234123 as a failing test case to reproduce the issue and verify the fix.

PR Checklist

• I read and included theses actions below

1. I have read the Contributing Guide
2. I have written documents and tests, if needed.

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