Fix Curl Code Generator for Multipart Form File

[leoferreiralima]

fixes #2224

Description

This PR fixes the issue #2224.

To resolve this issue i searched in httpsnippet code to understant how the lib expectes the file. Like the image below we should map a fileName property instead of value for files

Before:

After:

Contribution Checklist:

• The pull request only addresses one issue or adds one feature.
• The pull request does not introduce any breaking changes
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[Fabiensk]

Disclaimer: my knowledge and experience in NodeJS/Electron is limited.

Review: This change passes more contextual information to buildHarRequest and createPostData so when the target of the code generation is curl then the body file parameters value are passed with a fileName attribute to the HTTPSnippet library. In this library, we can that for the curl generation that a @ sign is added for file parameters of form requests.

This change could be also useful for other language targets such as python request, but it would require to be tested for each of them.
Possible improvement: leave a comment to mention that, for example before the line with client === 'curl':
// setting fileName could be also be beneficial for targets other than shell/curl, but would need to be tested