docs(javascript): Replace deprecated severity enums with string literals

Author: Luca Forstner

src/includes/enriching-events/breadcrumbs/breadcrumbs-example/javascript.mdx

@@ -2,6 +2,6 @@
 Sentry.addBreadcrumb({
   category: "auth",
   message: "Authenticated user " + user.email,
-  level: Sentry.Severity.Info,
+  level: "info",
 });
 ```

src/includes/set-level/javascript.mdx

@@ -8,7 +8,7 @@ To set the level within scope, you can call `setLevel()`:
 
 ```javascript
 Sentry.configureScope(function(scope) {
-  scope.setLevel(Sentry.Severity.Warning);
+  scope.setLevel("warning");
 });
 ```
 
@@ -20,8 +20,8 @@ Sentry.withScope(function(scope) {
 
   // The exception has the event level set by the scope (info).
   Sentry.captureException(new Error("custom error"));
-
 });
+
 // Outside of withScope, the Event level will have their previous value restored.
 // The exception has the event level set (error).
 Sentry.captureException(new Error("custom error 2"));

src/platforms/javascript/common/troubleshooting/index.mdx

@@ -389,12 +389,12 @@ document.body.addEventListener(
     if (event.target.tagName === "IMG") {
       Sentry.captureMessage(
         `Failed to load image: ${event.target.src}`,
-        Sentry.Severity.Warning
+        "warning" // message severiity level
       );
     } else if (event.target.tagName === "LINK") {
       Sentry.captureMessage(
         `Failed to load css: ${event.target.href}`,
-        Sentry.Severity.Warning
+        "warning" // message severiity level
       );
     }
   },