Set displayname for bot user with homeserver setting "enable_set_displayname: false"

Is it a configuration failure or a bug?

I want to set "enable_set_displayname: false" in the homeserver's configuration. When I try to create a new webhook I get the following error message because the bot user's display name cannot be set:

2023-06-16T12:27:16.556698424+02:00 ERROR 10:27:16:556 [MatrixHttpClient] (REQ-139) {
2023-06-16T12:27:16.556763834+02:00 errcode: 'M_FORBIDDEN',
2023-06-16T12:27:16.556787107+02:00 error: 'Changing display name is disabled on this server'
2023-06-16T12:27:16.556815351+02:00 }
2023-06-16T12:27:16.558166053+02:00 WARN 10:27:16:556 [Bridge] Failed to handle generic webhook MatrixError: M_FORBIDDEN: Changing display name is disabled on this server
2023-06-16T12:27:16.558231443+02:00 at doHttpRequest (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/http.js:95:15)
2023-06-16T12:27:16.558246972+02:00 at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
2023-06-16T12:27:16.558276541+02:00 at async descriptor.value (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/metrics/decorators.js:19:32)
2023-06-16T12:27:16.558290686+02:00 at async descriptor.value (/bin/matrix-hookshot/node_modules/matrix-bot-sdk/lib/metrics/decorators.js:19:32)
2023-06-16T12:27:16.558305885+02:00 at async GenericHookConnection.ensureDisplayname (/bin/matrix-hookshot/Connections/GenericHook.js:187:13)
2023-06-16T12:27:16.558318895+02:00 at async GenericHookConnection.onGenericHook (/bin/matrix-hookshot/Connections/GenericHook.js:307:9)
2023-06-16T12:27:16.558331307+02:00 at async /bin/matrix-hookshot/Bridge.js:402:25
2023-06-16T12:27:16.558343985+02:00 at async Promise.all (index 0)
2023-06-16T12:27:16.558358884+02:00 at async LocalMQ. (/bin/matrix-hookshot/Bridge.js:383:13) {
2023-06-16T12:27:16.558371440+02:00 body: {
2023-06-16T12:27:16.558383698+02:00 errcode: 'M_FORBIDDEN',
2023-06-16T12:27:16.558396354+02:00 error: 'Changing display name is disabled on this server'
2023-06-16T12:27:16.558409011+02:00 },
2023-06-16T12:27:16.558420096+02:00 statusCode: 400,
2023-06-16T12:27:16.558432083+02:00 errcode: 'M_FORBIDDEN',
2023-06-16T12:27:16.558443087+02:00 error: 'Changing display name is disabled on this server',
2023-06-16T12:27:16.558454364+02:00 retryAfterMs: undefined
2023-06-16T12:27:16.558465130+02:00 }

Is it possible to change this behavior?

Start in Connections/GenericHook.js at ensureDisplayname, identified in the stack trace around line 187, and trace its call from onGenericHook. Reproduce webhook creation with the homeserver setting enable_set_displayname: false and inspect the existing tests for generic webhooks. Done means webhook creation no longer fails because the bot display name cannot be changed.

Written by the indexing model from the issue text.