Allow batch sampler to not have a .sampler attribute #14536

Job	Run time
pl-cpu (macOS-14, lightning, 3.10, 2.1)	20m 25s
pl-cpu (ubuntu-20.04, lightning, 3.10, 2.1)	16m 3s
pl-cpu (windows-2022, lightning, 3.10, 2.1)	15m 12s
pl-cpu (macOS-14, lightning, 3.11, 2.2.2)	20m 24s
pl-cpu (ubuntu-20.04, lightning, 3.11, 2.2.2)	14m 39s
pl-cpu (windows-2022, lightning, 3.11, 2.2.2)	17m 48s
pl-cpu (macOS-14, lightning, 3.11, 2.3)	20m 46s
pl-cpu (ubuntu-20.04, lightning, 3.11, 2.3)	15m 44s
pl-cpu (windows-2022, lightning, 3.11, 2.3)	18m 0s
pl-cpu (macOS-14, lightning, 3.12, 2.4.1)	20m 44s
pl-cpu (ubuntu-22.04, lightning, 3.12, 2.4.1)	18m 47s
pl-cpu (windows-2022, lightning, 3.12, 2.4.1)	18m 27s
pl-cpu (macOS-14, lightning, 3.12, 2.5.1)	21m 1s
pl-cpu (ubuntu-22.04, lightning, 3.12, 2.5.1)	19m 54s
pl-cpu (windows-2022, lightning, 3.12, 2.5.1)	17m 35s
pl-cpu (macOS-14, pytorch, 3.12, 2.5.1)	21m 9s
pl-cpu (ubuntu-22.04, pytorch, 3.12, 2.5.1)	19m 44s
pl-cpu (windows-2022, pytorch, 3.12, 2.5.1)	18m 15s
pl-cpu (macOS-14, lightning, 3.9, 2.1, oldest)	21m 31s
pl-cpu (ubuntu-20.04, lightning, 3.9, 2.1, oldest)	13m 18s
pl-cpu (windows-2022, lightning, 3.9, 2.1, oldest)	14m 57s
pl-cpu (macOS-14, pytorch, 3.9, 2.1)	20m 24s
pl-cpu (ubuntu-20.04, pytorch, 3.9, 2.1)	15m 33s
pl-cpu (windows-2022, pytorch, 3.9, 2.1)	15m 41s
	7h 16m 1s

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