x-pack/filebeat/input/cel: add support for token authentication (#45359)

(cherry picked from commit 5c91c96)

# Conflicts:
#	docs/reference/filebeat/filebeat-input-cel.md

Author: efd6

CHANGELOG.next.asciidoc

@@ -430,6 +430,7 @@ otherwise no tag is added. {issue}42208[42208] {pull}42403[42403]
 - Update CEL mito extensions to v1.22.0. {pull}45245[45245]
 - Allow empty HTTPJSON cursor template value evaluations to be ignored by Fleet health status updates. {pull}45361[45361]
 - Reuse OAuth2 clients in HTTP JSON input where possible. {issue}34834[34834] {pull}44976[44976]
+- Add support for generalized token authentication to CEL input. {pull}45359[45359]
 
 *Auditbeat*