fix(core): Add lost scope tests & fix update case (#10738)

Noticed in the backport PR
https://github.com/getsentry/sentry-javascript/actions/runs/7971156054/job/21760458423?pr=10737,
where this failed, that we apparently lost some scope tests that used to
only be in the hub package. This forwards-ports them to v8, and also
fixes a case that was failing previously.

Author: mydea

packages/core/src/scope.ts

@@ -380,7 +380,7 @@ export class Scope implements ScopeInterface {
       if (scopeData.level) {
         this._level = scopeData.level;
       }
-      if (scopeData.fingerprint) {
+      if (scopeData.fingerprint.length) {
         this._fingerprint = scopeData.fingerprint;
       }
       if (scopeToMerge.getRequestSession()) {