refactor: Default values for `GlobalConfig.get` (#22967)

lib/config/decrypt.ts

lib/config/global.ts

lib/config/migrations/custom/extends-migration.ts

lib/config/presets/local/index.ts

lib/modules/datasource/npm/get.ts

lib/modules/datasource/npm/npmrc.ts

lib/modules/manager/azure-pipelines/extract.ts

lib/modules/manager/git-submodules/extract.ts

lib/modules/manager/git-submodules/update.ts

lib/modules/manager/gitlabci-include/extract.ts

lib/modules/manager/helmfile/extract.spec.ts

lib/modules/manager/npm/extract/pnpm.ts

lib/util/cache/package/decorator.ts

lib/util/exec/containerbase.ts

lib/util/exec/docker/index.ts

lib/util/exec/hermit.ts

lib/util/exec/index.ts

lib/util/fs/index.ts

lib/util/git/index.ts

lib/util/json-writer/editor-config.ts