API Remove silverstripe/campaign-admin integration support #1737

Job	Run time
CI / Generate matrix	19s
CI / Context	1s
CI / 8.3 prf-low mariadb phpunit all	2m 16s
CI / Check governance	0s
CI / 8.3 mysql80 phpunit all	2m 20s
CI / 8.3 mysql84 phpunit all	2m 13s
CI / 8.3 mysql80 phplinting	1m 47s
CI / 8.3 mysql80 endtoend root job1	10m 44s
CI / 8.3 mysql80 endtoend root job2	8m 34s
CI / 8.3 mysql80 endtoend root job3	9m 0s
CI / 8.3 mysql80 js	5m 7s
CI / Dispatch tag patch release	0s
	42m 21s

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