Add test case to ensure XML parse exceptions include filename and position

[xersion22]

Description

Currently, XML parse exceptions already include the filename at the beginning of the message. However, there is no automated test to ensure that the filename and position are consistently included in the exception message.

To prevent regressions, I propose adding a dedicated test in
XmlFileLoaderTest that asserts the exception message contains:

The filename (e.g., services31.xml)

The error details (This element is not expected)

The position (line X, column Y)

This would cover the case discussed in #61493.

I’d be happy to prepare a PR adding this test

[GromNaN]

Good idea, if it only impacts testing you can open a PR targeting 6.4.