refactor: [LW-11802] enable strict null checks #7550

Job	Run time
Build Lace	6m 49s
Prepare	6m 5s
When core changed	4s
When staking change	6s
Run Chromatic check: Core	3m 14s
Release package	5m 50s
Unit tests	8m 51s
Run Chromatic check: Staking	2m 48s
Smoke e2e tests (1)	3m 31s
Smoke e2e tests (2)	2m 35s
Smoke e2e tests (3)	2m 38s
Smoke e2e tests (4)	7m 4s
Smoke e2e tests (5)	3m 5s
Smoke e2e tests (6)	2m 47s
Smoke e2e tests (7)	3m 59s
Smoke e2e tests (8)	4m 3s
Smoke e2e tests (9)	2m 21s
Smoke e2e tests (10)	2m 1s
Smoke e2e tests (11)	2m 20s
Smoke e2e tests (12)	9m 11s
Smoke e2e tests (13)	6m 0s
Smoke e2e tests (14)	2m 45s
Smoke e2e tests (15)	2m 27s
Smoke e2e tests (16)	2m 22s
Process smoke e2e test reports	17s
	1h 33m 13s

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