fix: replace validator/isNumeric with a simple NaN & Finite check

[Lodin]

Fixes #2351.

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov[bot]]

Codecov Report

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

Project coverage is 95.00%. Comparing base (8e03da7) to head (27a0788).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2510 +/- ## ======================================= Coverage 95.00% 95.00% ======================================= Files 66 66 Lines 4548 4549 +1 Branches 661 662 +1 ======================================= + Hits 4321 4322 +1 Misses 182 182 Partials 45 45 ``` | [Flag](https://app.codecov.io/gh/vaadin/hilla/pull/2510/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=vaadin) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/vaadin/hilla/pull/2510/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=vaadin) | `95.00% <100.00%> (+<0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=vaadin#carryforward-flags-in-the-pull-request-comment) to find out more.

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[vaadin-bot]

This ticket/PR has been released with Hilla 24.5.0.alpha2 and is also targeting the upcoming stable 24.5.0 version.