fix(bitnami): use purl to detect bitnami pkg name

[DmitriyLewen]

Description

We use package name field instead of purl to detect package name to avoid case-insensitive issues:

trivy/pkg/sbom/io/decode.go

Lines 249 to 266 in c3192f0

	// pkgName returns the package name.
	// PURL loses case-sensitivity (e.g. Go, Npm, PyPI), so we have to use an original package name.
	func (m *Decoder) pkgName(pkg *ftypes.Package, c *core.Component) string {
	p := c.PkgIdentifier.PURL
	// A name from PURL takes precedence for CocoaPods since it has subpath.
	if c.PkgIdentifier.PURL.Type == packageurl.TypeCocoapods {
	return pkg.Name
	}
	if c.Group != "" {
	if p.Type == packageurl.TypeMaven || p.Type == packageurl.TypeGradle {
	return c.Group + ":" + c.Name
	}
	return c.Group + "/" + c.Name
	}
	return c.Name
	}

But bitnami is more focused on purl.
So After discussion we decided to use purl for bitnami packages.
See #6954 (reply in thread)

Discussed in #6954