EKF3: allow earth-frame fields to be estimated with an origin but no GPS #39649

Job	Run time
build (stm32f7, chibios, 10)	14m 38s
build (stm32h7, chibios, 10)	12m 53s
build (fmuv2-plane, chibios, 10)	1m 49s
build (periph-build, chibios, 10)	3m 42s
build (iofirmware, chibios, 10)	1m 51s
build (CubeOrange-bootloader, chibios, 10)	54s
build (fmuv3-bootloader, chibios, 10)	1m 4s
build (revo-bootloader, chibios, 10)	46s
build (stm32h7-debug, chibios, 10)	7m 21s
build (fmuv3, chibios, 10)	5m 16s
build (revo-mini, chibios, 10)	10m 38s
build (MatekF405-Wing, chibios, 10)	4m 57s
build (CubeOrange-ODID, chibios, 10)	2m 49s
build (CubeRedPrimary-bootloader, chibios, 10)	53s
build (configure-all, chibios, 10)	10m 7s
build (build-options-defaults-test, chibios, 10)	7m 51s
build (signing, chibios, 10)	9m 39s
build (CubeOrange-PPP, chibios, 10)	2m 6s
build (SOHW, chibios, 10)	13m 20s
build (Pixhawk6X-PPPGW, chibios, 10)	1m 10s
build (new-check, chibios, 10)	4m 25s
	1h 58m 9s

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