fix: Deployment Template HCL parsing with % keyword

[subhashish-devtron]

Description

Fixes #4009
The issue arose due to syntax conflict with HCL while parsing template for variables, which was in the format of %{some_value}

This syntax needed to be escaped before calling the parser so that HCL ignores this, since it was not intended by the user.
We made the current implementation of hcl parsing to also escape this format along with the already implemented escaping of the format @{some_value}

How Has This Been Tested?

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Checklist:

• The title of the PR states what changed and the related issues number (used for the release note).
• Does this PR requires documentation updates?
• I've updated documentation as required by this PR.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have tested it for all user roles.
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