packetbeat/module: fix upload of bundled ingest pipelines on Windows (#…

…41110) (#41116)

Detection of data stream identity was using os.PathSeparator which will
not match the path separator used by embed.FS which is always "/"[1].

[1]https://pkg.go.dev/embed#hdr-Directives

(cherry picked from commit f55bd8d)

Co-authored-by: Dan Kortschak <dan.kortschak@elastic.co>

CHANGELOG.next.asciidoc

@@ -207,6 +207,7 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 
 *Packetbeat*
 
+- Fix upload of bundled ingest pipelines on Windows. {pull}41110[41110]
 
 *Winlogbeat*
 

packetbeat/module/pipeline.go

@@ -22,7 +22,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"os"
 	"path"
 	"path/filepath"
 	"strings"
@@ -113,7 +112,10 @@ func readFile(filename string, info beat.Info) (p pipeline, err error) {
 	if err != nil {
 		return pipeline{}, err
 	}
-	ds, _, _ := strings.Cut(filename, string(os.PathSeparator))
+	ds, _, ok := strings.Cut(filename, "/")
+	if !ok {
+		return pipeline{}, fmt.Errorf("unexpected filename '%s': missing '/' between data stream and 'ingest'", filename)
+	}
 	p = pipeline{
 		id:       fileset.FormatPipelineID(info.IndexPrefix, "", "", ds, info.Version),
 		contents: updatedContent,