Failing to send a message leads to a crash

[Andrew Ferrazzutti]

Hookshot can crash if it fails to send a message event to a room. This is true for at least RSS feed update notices.

For example, sending a feed update notice in a room where Hookshot doesn't have a sufficient power level to send messages triggers this uncaught error:

ERROR 14:43:18:761 [MatrixHttpClient] (REQ-89) {
  errcode: 'M_FORBIDDEN',
  error: "You don't have permission to post that to the room. user_level (0) < send_level (50)"
}
/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/http.js:95
        throw new MatrixError_1.MatrixError(errBody, response.statusCode);
              ^

MatrixError: M_FORBIDDEN: You don't have permission to post that to the room. user_level (0) < send_level (50)
    at doHttpRequest (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/http.js:95:15)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async descriptor.value (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/metrics/decorators.js:19:32)
    at async descriptor.value (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/metrics/decorators.js:19:32)
    at async descriptor.value (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/metrics/decorators.js:19:32)
    at async descriptor.value (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/metrics/decorators.js:19:32)
    at async descriptor.value (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/metrics/decorators.js:78:32)
    at async FeedConnection.handleFeedEntry (/bin/matrix-hookshot/Connections/FeedConnection.js:173:9) {
  body: {
    errcode: 'M_FORBIDDEN',
    error: "You don't have permission to post that to the room. user_level (0) < send_level (50)"
  },
  statusCode: 403,
  errcode: 'M_FORBIDDEN',
  error: "You don't have permission to post that to the room. user_level (0) < send_level (50)",
  retryAfterMs: undefined
}

Hookshot should catch errors like this so that power level violations aren't fatal.

This issue means that someone can intentionally sabotage a shared Hookshot by inviting it to a room, stripping it of messaging privileges, and connecting it to a noisy RSS feed.