Decimal property editor: Flexibly parse decimal value with different separators (closes #20823)

[AndyButland]

Prerequisites

• I have added steps to test this contribution in the description below

Fixes: #20823

Description

This linked issue shows a server-side error message that appears to come about when there's a difference in decimal separators between the client and the server. I was able to replicate this via a failing unit test, that parses when the code from this PR is applied.

Testing

Verify min/max validation with the decimal property editor.

[Copilot]

Pull Request Overview

This PR fixes an issue where decimal property validation fails when the client and server use different decimal separators (e.g., comma vs. period). The solution adds flexible parsing logic that handles numeric types directly and falls back to culture-specific string parsing when needed.

Key changes:

• Enhanced TryParsePropertyValue method to handle multiple numeric types explicitly before attempting string parsing
• Added fallback to CultureInfo.CurrentCulture for string parsing when InvariantCulture fails
• Added unit test to verify validation works with Italian culture (comma decimal separator)

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/Umbraco.Core/PropertyEditors/DecimalPropertyEditor.cs	Replaced single-line TryParsePropertyValue with comprehensive implementation that checks for decimal/double/float types, handles IFormattable with InvariantCulture, and falls back to CurrentCulture parsing; also removed an empty line
tests/Umbraco.Tests.UnitTests/Umbraco.Core/PropertyEditors/DecimalPropertyValueEditorTests.cs	Added test case with Italian culture setting to verify validation works with different decimal separators

[Zeegaan]

Works like a charm 🚀