Handle network errors

[MrOrz]

In #401, we replaced the universal "Line bot is busy, or we cannot handle this message." timeout handling with a reply token collection mechanism.

However, it is possible that network errors occur so that the LINE client never gets the response back. Without proper error handling of network requests, the LINE user will wait indefinitely.

In this PR, we add back the error handling to long-running searchMedia() calls. When such error occurs, we would ask the user to try again later, which is a clear call-to-action message for the user.

Also, we add several logging labels to help debugging issues.

[coveralls]

Pull Request Test Coverage Report for Build 13481834874

Details

• 12 of 18 (66.67%) changed or added relevant lines in 6 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 90.761%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/webhook/lineClient.js	0	1	0.0%
src/lib/gql.ts	3	5	60.0%
src/webhook/handlers/askingArticleSubmissionConsent.ts	0	3	0.0%

Files with Coverage Reduction	New Missed Lines	%
src/webhook/handlers/askingArticleSubmissionConsent.ts	1	87.69%

Totals
Change from base Build 13479682573:	-0.2%
Covered Lines:	1129
Relevant Lines:	1199

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💛 - Coveralls