fix(flutter-web): use correct field when hiding unactionable source context errors (#63203)

change to `Source` to `source`

Relates to prev PR: #62998

Author: buenaflor

static/app/components/events/interfaces/crashContent/exception/actionableItems.spec.tsx

@@ -121,27 +121,27 @@ describe('Actionable Items', () => {
       {
         type: JavascriptProcessingErrors.JS_MISSING_SOURCES_CONTENT,
         data: {
-          Source: 'my_app/main.dart',
+          source: 'my_app/main.dart',
         },
       },
       {
         type: JavascriptProcessingErrors.JS_MISSING_SOURCES_CONTENT,
         data: {
-          Source:
+          source:
             'http://localhost:64053/Documents/flutter/packages/flutter/lib/src/material/ink_well.dart',
         },
       },
       {
         type: JavascriptProcessingErrors.JS_MISSING_SOURCES_CONTENT,
         data: {
-          Source:
+          source:
             'org-dartlang-sdk:///dart-sdk/lib/_internal/js_runtime/lib/async_patch.dart',
         },
       },
       {
         type: JavascriptProcessingErrors.JS_MISSING_SOURCES_CONTENT,
         data: {
-          Source:
+          source:
             'org-dartlang-sdk:///dart-sdk/lib/_internal/js_runtime/lib/js_helper.dart',
         },
       },

static/app/components/events/interfaces/crashContent/exception/actionableItemsUtils.tsx

@@ -133,7 +133,7 @@ export function shouldErrorBeShown(error: EventErrorData, event: Event) {
     event.sdk?.name === 'sentry.dart.flutter' &&
     error.type === JavascriptProcessingErrors.JS_MISSING_SOURCES_CONTENT
   ) {
-    const source: string | undefined = error.data?.Source;
+    const source: string | undefined = error.data?.source;
     if (
       source &&
       (source.includes('org-dartlang-sdk:///dart-sdk/lib/_internal') ||