SDK-1587 : fix cdn example not loading

Description

Web sdk example on the cdn at “https://cdn.branch.io/example.html” is failing to load the web sdk. It's missing part of the initialization code. Root cause : Variable COMPILER no longer exists in the make file and needs to be replaced by CLOSURE_COMPILER Workflow :

make file is invoked with release parameter from the deployment script here https://github.com/BranchMetrics/web-branch-deep-linking-attribution/blob/08274373460a96739f2ddd54a652168cfec3f423/deployment/deploy.sh#L79
make file internally converts example.template to example.html here https://github.com/BranchMetrics/web-branch-deep-linking-attribution/blob/08274373460a96739f2ddd54a652168cfec3f423/Makefile#L62
then the generated example.html is uploaded to s3, cdn inside the deployment script here https://github.com/BranchMetrics/web-branch-deep-linking-attribution/blob/08274373460a96739f2ddd54a652168cfec3f423/deployment/deploy.sh#L92

Fixes # (issue) : https://branch.atlassian.net/browse/SDK-1587

Type of change

Please delete options that are not relevant.

[x] 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

How Has This Been Tested?

Ran make script with release option and verified the generated example.html, verified linting, unit tests, integration tests have no regressions.

[ ] Unit test
[x] Integration test

JS Budget Check

Please mention the size in kb before abd after this PR

Files	Before	After
dist/build.js.	165kb	165kb
dist/build.min.js	78kb	78kb

Checklist:

[x] My code follows the style guidelines of this project
[x] I have performed a self-review of my own code
[x] I have commented my code, particularly in hard-to-understand areas
[x] I have made corresponding changes to the documentation
[x] My changes generate no new warnings
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes
[x] Any dependent changes have been merged and published in downstream modules
[x] I have checked my code and corrected any misspellings

Mentions:

List the person or team responsible for reviewing proposed changes.

BranchMetrics / web-branch-deep-linking-attribution