Fix plugin crash when variable is passed for Options

[niveathika]

Purpose

$subject

Part of ballerina-platform/ballerina-library#2536

Examples

N/A

Checklist

• Linked to an issue
• Updated the changelog
• Added tests

[codecov]

Codecov Report

Merging #104 (dfb38a8) into main (d18ca4d) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main     #104   +/-   ##
=========================================
  Coverage     85.30%   85.30%           
  Complexity      182      182           
=========================================
  Files            16       16           
  Lines           633      633           
  Branches        139      139           
=========================================
  Hits            540      540           
  Misses           51       51           
  Partials         42       42           

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