Switch OIDC primarily to new `/auth_metadata` API #10764

Job	Run time
ESLint	32s
Workflow Lint	16s
Node.js example	23s
Analyse Dead Code	16s
JSDoc Checker	39s
Downstream tsc element-web	0s
Typescript Syntax Check	27s
Downstream Typescript Syntax Check	1s
	2m 34s

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