chore: remove `@glint/environment-ember-*` #231

Job	Run time
Slow tests: defaults with pnpm	54s
Lint	17s
Slow tests: defaults with npm	1m 31s
Tests (addon-location)	30s
Tests (test-app-location)	20s
Tests (monorepo with pnpm)	25s
Tests (rollup-build)	16s
Slow tests: typescript with pnpm	1m 1s
Tests (addon-only)	21s
Tests (declarations-configuration)	31s
Tests (monorepo with npm)	17s
Slow tests: typescript with npm	1m 31s
Slow tests: try-scenarios	1m 59s
	9m 53s

Provide feedback