Fix converting xml to record type with rest type and required fields

[prakanth97]

Purpose

Fixes: #6659

public function main() returns error? {
    string xmlStr = string `
    <Data>
        <field2>
            <str2>2</str2>
            <str1>1</str1>
        </field2>
    </Data>
    `;
    record {|
        record {
            string str1;
        } field2;
    |} rec = check xmldata:parseString(xmlStr);
}

In the above case issue is element str1 is convert to anydata (int runtime value) instead of string. This is due to the all the elements after str2 convert to the rest type. In this PR we have fixed this wrong behaviour.

Examples

Checklist

• Linked to an issue
• Updated the changelog
• Added tests
• Updated the spec
• Checked native-image compatibility

[prakanth97]

This PR depends on #20.

[codecov]

Codecov Report

Attention: Patch coverage is 82.69231% with 9 lines in your changes missing coverage. Please review.

Project coverage is 86.46%. Comparing base (5173362) to head (a32e34e).
Report is 51 commits behind head on main.

Files	Patch %	Lines
...io/ballerina/lib/data/xmldata/utils/DataUtils.java	50.00%	3 Missing and 3 partials ⚠️
...a/io/ballerina/lib/data/xmldata/xml/XmlParser.java	92.50%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main      #26      +/-   ##
============================================
+ Coverage     85.92%   86.46%   +0.53%     
- Complexity      524      556      +32     
============================================
  Files            22       25       +3     
  Lines          2281     2416     +135     
  Branches        513      529      +16     
============================================
+ Hits           1960     2089     +129     
+ Misses          195      187       -8     
- Partials        126      140      +14     

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