[FSSDK-9605] add sendBeacon event dispatcher and test #587

Job	Run time
lint	1m 17s
unit_tests (8)	1m 34s
crossbrowser_and_umd_unit_tests	2m 46s
test_sub_packages (packages/utils)	25s
unit_tests (9)	1m 53s
test_sub_packages (packages/event-processor)	27s
unit_tests (10)	1m 53s
test_sub_packages (packages/logging)	21s
unit_tests (12)	1m 52s
test_sub_packages (packages/datafile-manager)	2m 21s
unit_tests (14)	2m 19s
unit_tests (16)	2m 14s
unit_tests (18)	1m 57s
integration_tests / test	8s
fullstack_production_suite / test	7s
lint_markdown_files / lint	1m 10s
Coveralls coverage	10s
	22m 54s

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