Fix strpos check for decimal point in Calculator::trim()

Summary

In modules/price/src/Calculator.php, the check for a decimal point uses strpos($number, '.') != FALSE, which fails when the decimal point is at position 0 (e.g. '.5'). In that case strpos returns 0, and 0 != FALSE is false, so the decimal point is not detected.

Steps to reproduce

1. Call Calculator::trim('.5') or any string where the decimal point is at index 0.
2. Observe that trailing zeros are not stripped because the decimal point is not recognized.

Proposed solution

Replace the loose comparison with either:

• strpos($number, '.') !== false, or
• str_contains($number, '.') (PHP 8+).

Impact

This is a common PHP pitfall: when checking for substring presence, use strict comparison with false or str_contains() in PHP 8+.