improved code style

[Tautve]

improved code style by importing some use statements, substr replacing with strpos

[adhocore]

helo, thanks for this PR. im gonna accept this PR if the build passes and you kindly can format the commit message to angular format (as are other commits before) : https://github.styleci.io/analyses/prOrAR

however since it is not feature or fix or significant refactor - i don't know if it should be #hacktoberfest-accepted though.

edit: since you are a first time contributor, as a courtesy i will mark it as #hacktoberfest-accepted :)
(pls address the comment above though)

[adhocore]

seems you didnt check https://github.styleci.io/analyses/prOrAR
also might need to rebase commit msg for this one a7037d6

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da7158a should be:

refactor: changed the order of use statements in JWT.php