[9.1](backport #47443) Replace gokrb5/v8/spnego with elastic fork (#47496)

* Replace `gokrb5/v8/spnego` with elastic fork (#47443)

* Replace gokrb5/v8/spnego with elastic fork

(cherry picked from commit 20c03b0)

# Conflicts:
#	go.mod

* fix conflicts

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Co-authored-by: Khushi Jain <khushi.jain@elastic.co>

Author: mergify[bot]