Fix ErrorMessageOverride collision with classname

[andrueastman]

Fixes #4893

In summary, this PR

• Updates the ReplaceReservedExceptionPropertyNames method to also rename the error class if it is the same name as a reserved class to avoid collision with class name and property name.
• Updates the AddPrimaryErrorMessage to rename existing matching properties if they already exist in the error model to avoid information/property loss (otherwise we will fail to add the override and lead to invalid generation)
• Add tests to validate the scenarios.

Essentially, in a scenario where a ErrorMessageOverride property kind named message is added,

• if the error model class is also called message, the model class will be renamed to avoid class and property name collision.
• if a property with the same name already exists in the model, the pre-existing property is renamed to ensure the suitable override is added (if the type does not match).
• otherwise, normal behavior of adding the override property will be used.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
94.3% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud