[Refactor] Move MatchingLabels to association.go [2/N]

[rueian]

Following #2045

We like to move all client.MatchingLabels{utils.RayClusterLabelKey: instance.Name, utils.RayNodeTypeLabelKey: string(rayv1.HeadNode)} to the association.go, so that we can maintain consistency in the association methods by not scattering MatchingLabels everywhere.

Including:

kuberay/ray-operator/controllers/ray/raycluster_controller.go

Line 547 in 9068102

filterLabels := client.MatchingLabels{utils.RayClusterLabelKey: instance.Name, utils.RayNodeTypeLabelKey: string(rayv1.HeadNode)}

kuberay/ray-operator/controllers/ray/raycluster_controller.go

Line 289 in 9068102

filterLabels := client.MatchingLabels{utils.RayClusterLabelKey: instance.Name, utils.RayNodeTypeLabelKey: string(rayv1.RedisCleanupNode)}

kuberay/ray-operator/controllers/ray/raycluster_controller.go

Line 1453 in 9068102

filterLabels := client.MatchingLabels{

[owenowenisme]

@rueian
Hi, I would like to help with this.