[AppConfig] Allow importing key-values with unicode characters from file

[avanigupta]

Description

While importing key-values from a file, if the key or value contains a non-ASCII character, we fail to parse the file and throw syntax error. Since AppConfig allows unicode characters in key and values, we should be able to import them from file.

Reported in customer issue #513.

Testing Guide
Trying to import this json file with unicode characters should succeed:

{
  "User’s Name": "John",
  "Temperature": "98º",
  "Chinese": "汉"
}

az appconfig kv import -s file --format json --auth-mode login --endpoint https://test-appconfig-00.azconfig.io --path <filePath> --yes

History Notes

[Component Name 1] BREAKING CHANGE: az command a: Make some customer-facing breaking change.
[Component Name 2] az command b: Add some customer-facing feature.

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[avanigupta]

cc @shenmuxiaosen

[yonzhan]

AppConfig

[shenmuxiaosen]