EmbedAllSources causes T4 sources to fail compliation

I hope I'm reporting this in the correct repo.

We're running a project which contains TextTemplatingFilePreprocessor generations.
As we are generating a lot of code, I've added the EmbedAllSources flag to our projects and I began seeing this issue:

```
#line 1 "C:\Gitworkspace\S6_3\pc\Src\PressSDK\CodeGenerators\Press\Buzzerable\BuzzerableManagers\Templates\BuzzerableManagerInterfacesGenerator.tt"
```

For the generated files, for example:
```
///
/// Class to produce the template output
///

#line 1 "C:\Gitworkspace\S6_3\pc\Src\PressSDK\CodeGenerators\Press\Buzzerable\BuzzerableManagers\Templates\BuzzerableManagerInterfacesGenerator.tt"
[global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.VisualStudio.TextTemplating", "17.0.0.0")]
public partial class BuzzerableManagerInterfacesGenerator : BuzzerableManagerInterfacesGeneratorBase
{
#line hidden
///
/// Create the template output
///
public virtual string TransformText()

```
(The issue appears for all generated files' line pragma)

The issue is, that we do NOT generate the files during build (as there are other bugs there :) ) meaning, we generate & TT's output generation in source control

So the problem is that the `#line` is pointing toward the last person who generated the generated file, meaning, I will not have it on my computer while building.

Without EmbedAllSources, there is no issue.

To reproduce, create any file with a `#line` pragma pointing toward an invalid path and activate the flag