Incorrect placeholder value for creating new personal token

[Twi1ightSparkle]

Describe the bug
A customer reported

When using the “Add” button on Personal tokens, the form shows a placeholder value of “30” for the expiry date in days. This placeholder is not respected, and the help text underneath is correct in that leaving the field blank makes a token which does not expire.

To Reproduce
Steps to reproduce the behavior:

1. Create a Personal Token leaving expiry empty

Expected behavior
Placeholder value to reflect the default behaviour when expiry is not defined

Screenshots
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Desktop (please complete the following information):
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Smartphone (please complete the following information):
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Additional context
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