refactor(template): change source_location in github template for aggregated packages

[DmitriyLewen]

Description

We use target field for source_location in github template.
But we aggregate some packages:

trivy/pkg/fanal/applier/docker.go

Lines 263 to 291 in fb36c4e

	func aggregate(detail *ftypes.ArtifactDetail) {
	var apps []ftypes.Application
	aggregatedApps := map[ftypes.LangType]*ftypes.Application{
	ftypes.PythonPkg: {Type: ftypes.PythonPkg},
	ftypes.CondaPkg: {Type: ftypes.CondaPkg},
	ftypes.GemSpec: {Type: ftypes.GemSpec},
	ftypes.NodePkg: {Type: ftypes.NodePkg},
	ftypes.Jar: {Type: ftypes.Jar},
	}
	for _, app := range detail.Applications {
	a, ok := aggregatedApps[app.Type]
	if !ok {
	apps = append(apps, app)
	continue
	}
	a.Libraries = append(a.Libraries, app.Libraries...)
	}
	for _, app := range aggregatedApps {
	if len(app.Libraries) > 0 {
	apps = append(apps, *app)
	}
	}
	// Overwrite Applications
	detail.Applications = apps
	}

For these packages target is Python, Java, etc.
This is problem for GitHub UI - #5998.
We need to use Results.Packages.FilePath for these packages.

But filePath for image scans can be large (e.g. "FilePath": "usr/local/lib/python3.12/site-packages/pip-23.2.1.dist-info/METADATA").
It might make sense to use image name for image mode.

Discussed in #5998