FINERACT-2402: Replace delimiter : with = in kafka-server.env

[Aman-Mittal]

Description

Describe the changes made and why they were made.

Created PR after feedback from my previous PR: #5131

Although it is not necessary but using : in env variables may cause in older versions of docker compose. So replacing : to = as standard way of keeping .env file

Ignore if these details are present on the associated Apache Fineract JIRA ticket.

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[Aman-Mittal]

@meonkeys This PR is for fixing delimiters.

[meonkeys]

LGTM, thanks @Aman-Mittal . I'll merge once tests pass.