Feature export network as har

[hrajwade96]

Replace this paragraph with a description of what this PR is changing or adding, and why. Consider including before/after screenshots.

List which issues are fixed by this PR.

Please add a note to packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md if your change requires release notes. Otherwise, add the 'release-notes-not-required' label to the PR.

Pre-launch Checklist

• [ ] I read the Contributor Guide and followed the process outlined there for submitting PRs.
• [ ] I read the Tree Hygiene wiki page, which explains my responsibilities.
• [ ] I read the Flutter Style Guide recently, and have followed its advice.
• [ ] I signed the CLA.
• [ ] I listed at least one issue that this PR fixes in the description above.
• [ ] I updated/added relevant documentation (doc comments with ///).
• [ ] I added new tests to check the change I am making, or there is a reason for not adding tests.

If you need help, consider asking for help on Discord.

[google-cla[bot]]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.