fix: handle empty content correctly in FilesStore saveFile() (#1381)

* Fix FilesStore: Handle empty content correctly in saveFile(). Happens when user creates files in the web terminal

* updated logic

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Co-authored-by: Anirban Kar <thecodacus@gmail.com>

app/lib/stores/files.ts

@@ -115,7 +115,7 @@ export class FilesStore {
 
       const oldContent = this.getFile(filePath)?.content;
 
-      if (!oldContent) {
+      if (!oldContent && oldContent !== '') {
         unreachable('Expected content to be defined');
       }