docs: Update README with an important note

[nimafarzin-pr]

Description

Investigating the WiFi name retrieval issue took quite a bit of time. While reviewing the package code and comments, I discovered that active GPS is required for getWifiName to function so I updated network_info_plus readme and added a note that starting with Android 8.0, turning on GPS (high accuracy) is necessary to get the SSID (your Wi-Fi network name).

Related Issues

WiFi name was not being received

e.g.

• Related #99

Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I titled the PR using Conventional Commits.
• I did not modify the CHANGELOG.md nor the plugin version in pubspec.yaml files.
• All existing and new tests are passing.
• The analyzer (flutter analyze) does not report any problems on my PR.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• Yes, this is a breaking change (please indicate that with a ! in the title as explained in Conventional Commits).
• No, this is not a breaking change.

[vbuberen]

Hi there. Thanks for your contribution, but I would ask you to comply with requirements we have to PRs:

• Name pull request correctly.
• Fill in the PR template with more details. Namely, provide link to the documentation/info about the change you are adding.
• Match the formatting to the rest of the README.

Finally, would be good to have this note also here https://github.com/fluttercommunity/plus_plugins/blob/main/docs/network_info_plus/usage.mdx so the website documentation is updated as well.