fix: only set backgroundColor in default-app for default index.html (#28792)
fix: only set backgroundColor in default-app for default index.html (#28792)


gerhardberger/electron,bpasero/electron,electron/electron,electron/electron,gerhardberger/electron,bpasero/electron,gerhardberger/electron,gerhardberger/electron,bpasero/electron,bpasero/electron,electron/electron,bpasero/electron,gerhardberger/electron,electron/electron,electron/electron,bpasero/electron,gerhardberger/electron,electron/electron,bpasero/electron,gerhardberger/electron,electron/electron