fix(telemetry): stop flushErrorReports throwing out of the boot path

Self-review catch. `reportError` guarded its dispatch but `flushErrorReports`
did not, and that one is called directly from `main.ts` and `bootstrap.ts`.
A sink that threw during the flush would have taken the whole app down instead
of the single report it failed to deliver — the exact failure the module exists
to prevent.

Also stops forwarding an explicit `level: undefined` into the RUM context when
no level was given.

Test verified red-green: it fails with the guard removed.

Author: christian-byrne

src/platform/telemetry/reportError.test.ts

@@ -137,6 +137,21 @@ describe('reportError', () => {
     expect(context).toMatchObject({ api_endpoint: '/settings/{key}' })
   })
 
+  it('does not throw out of flushErrorReports when a sink throws', async () => {
+    sentryLive(false)
+    datadogLive(false)
+    const { reportError, flushErrorReports } = await loadReportError()
+
+    reportError(new Error('early'), { errorType: 'resource_load_error' })
+
+    datadogLive(true)
+    addError.mockImplementation(() => {
+      throw new Error('datadog exploded')
+    })
+
+    expect(() => flushErrorReports()).not.toThrow()
+  })
+
   it('does not throw when a sink throws', async () => {
     captureException.mockImplementation(() => {
       throw new Error('sentry exploded')

src/platform/telemetry/reportError.ts

@@ -57,7 +57,7 @@ function dispatch(error: Error, options: ReportErrorOptions): boolean {
       ...context,
       ...tags,
       error_type: errorType,
-      level
+      ...(level ? { level } : {})
     })
   }
 
@@ -67,14 +67,22 @@ function dispatch(error: Error, options: ReportErrorOptions): boolean {
 /**
  * Drains reports buffered before a sink came up. Safe to call repeatedly;
  * a no-op while every sink is still inert.
+ *
+ * Callers are `main.ts` and `bootstrap.ts` on the boot path, so this must
+ * never throw: a sink that explodes here would take the whole app down
+ * instead of the one report it failed to deliver.
  */
 export function flushErrorReports(): void {
   if (!pendingReports.length) return
   if (!isSentryEnabled() && !isDatadogRumLive()) return
 
   const drained = pendingReports.splice(0, pendingReports.length)
   for (const { error, options } of drained) {
-    dispatch(error, options)
+    try {
+      dispatch(error, options)
+    } catch (reporterFailure) {
+      console.error('[reportError] failed to flush', reporterFailure, error)
+    }
   }
 }