chore(mac): retry notarization/codesigning on network error

Retry notarization when we get network failure or server failure:

```
11:20:24 [mac/setup] Uploading Install Keyman.zip to Apple for notarization
11:20:51 Error: HTTPError(statusCode: nil, error: Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." UserInfo={_kCFStreamErrorCodeKey=60, NSUnderlyingError=0x6000003b5530 {Error Domain=kCFErrorDomainCFNetwork Code=-1001 "(null)" UserInfo={_kCFStreamErrorCodeKey=60, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask .<2>, _NSURLErrorRelatedURLSessionTaskErrorKey=(
11:20:51 "LocalDataTask .<2>"
11:20:51 ), NSLocalizedDescription=The request timed out., NSErrorFailingURLStringKey=https://appstoreconnect.apple.com/notary/v2/submissions?, NSErrorFailingURLKey=https://appstoreconnect.apple.com/notary/v2/submissions?, _kCFStreamErrorDomainKey=1})
11:20:51 Process exited with code 1
```

https://build.palaso.org/buildConfiguration/Keyman_KeymanMac_PullRequests/435316?buildTab=log&linesState=6250&logView=flowAware&focusLine=12179

And the same on codesigning:

```
06:27:32 ../Keyman4MacIM/output/Install Keyman.app: replacing existing signature
06:27:32 ../Keyman4MacIM/output/Install Keyman.app: The timestamp service is not available.
06:27:32 In subcomponent: /Users/mcdurdin/buildAgent/work/99b311828f4ee7c/keyman/mac/Keyman4MacIM/output/Install Keyman.app/Contents/MacOS/textinputsource
06:27:32 Process exited with code 1
```

https://build.palaso.org/buildConfiguration/Keyman_KeymanMac_PullRequests/438334?buildTab=log&linesState=6225&logView=flowAware&focusLine=12135