Avoid type promotion when computing permittivity #534

Job	Run time
tests-bayer-jax-0_4_27	1m 51s
pre-commit	48s
tests-ceviche-jax-0_4_27	1m 16s
tests-bayer-jax-latest	1m 33s
tests-ceviche-jax-latest	1m 28s
tests-diffract-jax-0_4_27	2m 4s
tests-diffract-jax-latest	2m 0s
tests-extractor-jax-0_4_27	1m 42s
tests-extractor-jax-latest	1m 44s
tests-library-jax-0_4_27	3m 39s
tests-library-jax-latest	3m 14s
tests-metalens-jax-0_4_27	1m 33s
tests-metalens-jax-latest	1m 31s
tests-misc-jax-0_4_27	1m 6s
tests-misc-jax-latest	1m 5s
validate-types-and-docstrings	1m 10s
	27m 44s

Provide feedback