fix: add --no-flat flag to browserify script in AEL

[stevengum]

Fixes #3274

Description

In #3222, the tinyified adaptive-expressions browser.js was malformed and caused Composer to break. This PR fixes the break by disabling a plugin in tinyify.

Using ce99c67, the browserified-and-tinyified lib/browser.js is 1,091 KB in size and a 40 KB increase after #3222.

Specific Changes

• add --no-flat flag to browserify script in AEL

Testing

1. Cloned and setup BotFramework-Composer repo per README instructions
2. Used yarn link to symlink a local clone of the JS repository
3. Built JS repo @main (729a577)
4. Ran yarn startall in BotFramework-Composer/Composer and observed bug
5. Applied fix to adaptive-expressions package.json's "browserify" script
6. Rebuilt adaptive-expressions and Composer
7. Ran yarn startall in BotFramework-Composer/Composer
8. Verified Composer started without bug

[coveralls]

Pull Request Test Coverage Report for Build 552627439

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 4 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.03%) to 84.86%

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Files with Coverage Reduction	New Missed Lines	%
libraries/adaptive-expressions/src/triggerTrees/node.ts	2	95.26%
libraries/adaptive-expressions/src/triggerTrees/trigger.ts	2	61.92%

Totals
Change from base Build 549312792:	-0.03%
Covered Lines:	18552
Relevant Lines:	20846

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💛 - Coveralls