WS-1347: Remove fallback command.

[shayneahchoon]

Resolves JIRA: https://bbc.atlassian.net/browse/WS-1347

Summary

Removes fallback command but keeps Error messages. Example error message being propagated:

Running /integration/utils/runTests/index.js returned an error => 
 Error: Error: Command failed: yarn start
node:internal/modules/cjs/loader:1228
  throw err;
  ^

Error: Cannot find module '/Users/ahchos01/Desktop/WORLD_NEWS/simorgh/ws-nextjs-app/build/standalone/ws-nextjs-app/server2.js'
    at Function._resolveFilename (node:internal/modules/cjs/loader:1225:15)
    at Function._load (node:internal/modules/cjs/loader:1055:27)
    at TracingChannel.traceSync (node:diagnostics_channel:322:14)
    at wrapModuleLoad (node:internal/modules/cjs/loader:220:24)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:170:5)
    at node:internal/main/run_main_module:36:49 {
  code: 'MODULE_NOT_FOUND',
  requireStack: []
}

Node.js v22.14.0

    at file:///Users/ahchos01/Desktop/WORLD_NEWS/simorgh/src/integration/utils/runTests/index.js:62:16
    at ChildProcess.exithandler (node:child_process:421:5)
    at ChildProcess.emit (node:events:518:28)
    at maybeClose (node:internal/child_process:1101:16)
    at ChildProcess._handle.onexit (node:internal/child_process:304:5)

Code changes

• Removed fallback command.

Testing

1. List the steps required to test this PR.

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