Make OutParameter get function parameter optional

[niveathika]

Purpose

$subject

Part of ballerina-platform/ballerina-library#2388

Examples

Checklist

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

[codecov]

Codecov Report

Merging #445 (2ffc216) into master (bd1fcce) will increase coverage by 0.07%.
The diff coverage is 84.21%.

@@            Coverage Diff             @@
##           master     #445      +/-   ##
==========================================
+ Coverage   80.16%   80.24%   +0.07%     
==========================================
  Files          37       37              
  Lines        3560     3563       +3     
  Branches      744      745       +1     
==========================================
+ Hits         2854     2859       +5     
+ Misses        481      480       -1     
+ Partials      225      224       -1     

Impacted Files	Coverage Δ
ballerina/types.bal	92.43% <83.01%> (ø)
...a/stdlib/sql/nativeimpl/OutParameterProcessor.java	58.73% <100.00%> (+2.06%)	⬆️
.../io/ballerina/stdlib/sql/utils/ErrorGenerator.java	81.03% <0.00%> (+3.44%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update bd1fcce...2ffc216. Read the comment docs.