fix: delete the temp file when its write fails

[nkuprins]

Closed: #1137

Purpose of the pull request

As title
Out of scope: when encryption fails, finish() still writes the unencrypted workbook to the caller's stream. That is tracked separately in #1135.

What's changed?

• WriteContextImpl#doOutputStreamEncrypt07 deletes the temp file in one outer finally.
• The temp file's FileOutputStream is a try-with-resources, so it is closed even when workbook.close() throws.
• The delete is skipped when the temp file doesn't exist. Without this, a failure to open it would report "Can not delete temp File!" instead of the FileNotFoundException.

When two steps fail, only one exception can be thrown. These are the cases where doOutputStreamEncrypt07 now throws a different one than on main:

What fails	Thrown on main	Thrown in this PR
Both writing the temp file and closing its stream	the close error; the write error is lost	the write error, with the close error attached as suppressed
Both writing the temp file and deleting it	the write error, but the delete was never attempted, so the unencrypted temp file stayed on disk	"Can not delete temp File!"; the write error is lost
Both closing the workbook and closing the stream	the workbook close error	the same, with the stream close error attached as suppressed

Tests

New cases in EncryptDataTest:

• xlsxStreamPasswordWrite_tempFileWriteFails_deletesTempFile: fails on main.
• xlsxStreamPasswordWrite_workbookCloseFails_closesTempFileStream: fails on main.
• xlsxStreamPasswordWrite_workbookCloseFails_deletesTempFile
• xlsxStreamPasswordWrite_encryptedWriteFails_deletesTempFile
• xlsxStreamPasswordWrite_tempFileOpenFails_reportsOpenError

The last three pass on main too, since those paths already cleaned up. They guard against regressions.

Checklist

• I have read the Contributor Guide.
• I have written the necessary doc or comment.
• I have added the necessary unit tests and all cases have passed.