Support Attachment size restriction during upload

[deepikaSingh2711]

Describe your changes

This PR introduces README update for file size validation functionality to the SDM CAP plugin, allowing developers to enforce maximum attachment sizes during upload operations

As the cds-feature-attachments module introduced Enhanced File Attachment Validation with a Maximum Size annotation in its 1.3.0 release.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist before requesting a review

• I follow Java Development Guidelines for SAP
• I have tested the functionality on my cloud environment.
• I have provided sufficient automated/ unit tests for the code.
• I have increased or maintained the test coverage.
• I have ran integration tests on my cloud environment.
• I have validated blackduck portal for any vulnerability after my commit.

Upload Screenshots/lists of the scenarios tested

• I have Uploaded Screenshots or added lists of the scenarios tested in description