Moving flag into section for esp_event linker file (IDFGH-1007)

[tomseago]

If this flag is at the top level the linker generation script throws an error.

It appears that when this file was added an incorrect syntax was used. This pull request follows the syntax found for other components and allows the build of hello world to succeed. This fixes #3295

[CLAassistant]

All committers have signed the CLA.

[sieren]

I've filed a PR for this earlier as well: #3322

Can you get away without the default section (as in mine)? I recall running into some issues without it.

[renzbagaporo]

@tomseago @sieren

The top level flag check syntax was added recently. Unfortunately the recent pyparsing 2.4.0 might have introduced regression which affects our grammar, we've submitted an issue to the PyParsing Github issue tracker and waiting on a response.

re. the abscence of default section, an update is coming to use default mappings when no conditions match; removing this requirement. But for now having the final else block is more correct.

[igrr]

Closing as this got fixed in 2522268 (but it took another week for the fix to get synced to Github, sorry about that!)