[swift5 client] fix filename for binary downloads

Created by: gretzki

Problem:

When a file download is handled within URLSessionImplementations, the filename is retrieved via the header Content-Disposition part of the response. The header is looked for an entry starting with filename=. But the search is skipped too early, since the loop is exited if the first iteration does not match.

Example:

Try to download a file with a swift5 client for a spec like this:

  /PublicDocument/Download:
    get:
      tags:
        - Public Area
      description: 'Document Download for Public Documents. Login not Required'
      parameters:
        - $ref: '#/components/parameters/queryId'
      responses:
        '200':
          description: 'OK'
          content:
            application/pdf:
              schema:
                type: string
                format: binary

When downloading from a server, the response header could have an answer like so:

Content-Disposition: attachment; filename=downloaded.pdf; filename*=UTF-8''downloaded.pdf

There, the server says to use downloaded.pdf as filename. But the actual implementation of the swift5 client will exit after checking attachment and won't find filename= in the next section (separated by semicolon).

Solution:

Simply replacing break with continue in the matching logic inside the loop fixes the algorithm.

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