fix(core): execute buffered requests during load API

[MoumitaM]

Description of the change

• Updated request buffering part during SDK initialization.
• Added a call to execute buffered requests at the end of load API.

Type of change

• [x] Bug fix (non-breaking change that fixes an issue)
• [ ] New feature (non-breaking change that adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Related issues

Fix #665

Checklists

Development

• [ ] Lint rules pass locally
• [ ] The code changed/added as part of this pull request has been covered with tests
• [ ] All tests related to the changed code pass in development

Code review

• [ ] This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• [ ] "Ready for review" label attached to the PR and reviewers mentioned in a comment
• [ ] Changes have been reviewed by at least one other engineer
• [ ] Issue from task tracker has a link to this pull request

---

This change is 

[github-actions[bot]]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
Core - CDN	39.18 KB (+0.11% 🔺)	784 ms (+0.11% 🔺)	662 ms (-32.32% 🔽)	1.5 s
All Integrations - CDN	581.85 KB (0%)	11.7 s (0%)	3.4 s (+16.31% 🔺)	15 s
Core - NPM	39.37 KB (+0.12% 🔺)	788 ms (+0.12% 🔺)	553 ms (+8.48% 🔺)	1.4 s