fix: Initialize output in `RefittingAlgorithm` #14810

Job	Run time
lcg (centos7-lcg100-gcc10)	7m 4s
linux_ubuntu	5m 45s
lcg (centos7-lcg101-gcc11)	6m 8s
lcg (centos8-lcg100-gcc10)	8m 25s
linux_ubuntu_extra (ubuntu2004, 17)	8m 43s
linux-nodeps (centos8-lcg100-gcc10)	22m 0s
linux_ubuntu_extra (ubuntu2204_cpp20, 20)	5m 55s
lcg (centos8-lcg101-gcc11)	8m 52s
linux_ubuntu_extra (ubuntu2204_clang, 17)	6m 9s
cuda	2m 18s
macos	8m 48s
sycl	2m 38s
linux_examples_test	23m 30s
linux_physmon	30m 50s
linux_physmon_perf_report	0s
	2h 27m 5s

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