Avoid enabling skipLibCheck and fix the error while this option is disabled

[linlin-s]

Description:

When the skipLibCheck option is disabled in tsconfig.json, we encounter web-specific errors from Selenium and BrowserStack, which are not directly relevant to our core dependencies. Therefore, these type-checking errors should not significantly impact our project. To facilitate the unblocking of our build process, we have temporarily enabled skipLibCheck. However, we acknowledge that bypassing type checking entirely might lead to potential issues. To ensure we can effectively trace and address any future problems, we open this issue as a reference point to help identify the root cause.

What exactly does skipLibCheck do?
When set to true, skipLibCheck allows TypeScript to skip type checking for declaration files. This can expedite the build process but at the risk of overlooking type-related errors in these files.

Here is the error message

node_modules/@theintern/digdug/BrowserStackTunnel.d.ts(14,9): error TS2611: 'auth' is defined as a property in class 'Tunnel', but is overridden here in 'BrowserStackTunnel' as an accessor.
node_modules/@theintern/digdug/BrowserStackTunnel.d.ts(15,9): error TS2611: 'executable' is defined as a property in class 'Tunnel', but is overridden here in 'BrowserStackTunnel' as an accessor.
node_modules/@theintern/digdug/BrowserStackTunnel.d.ts(17,9): error TS2611: 'url' is defined as a property in class 'Tunnel', but is overridden here in 'BrowserStackTunnel' as an accessor.
node_modules/@theintern/digdug/SeleniumTunnel.d.ts(14,9): error TS2611: 'directory' is defined as a property in class 'Tunnel', but is overridden here in 'SeleniumTunnel' as an accessor.
node_modules/@theintern/digdug/SeleniumTunnel.d.ts(15,9): error TS2611: 'executable' is defined as a property in class 'Tunnel', but is overridden here in 'SeleniumTunnel' as an accessor.
node_modules/@theintern/digdug/SeleniumTunnel.d.ts(17,9): error TS2611: 'url' is defined as a property in class 'Tunnel', but is overridden here in 'SeleniumTunnel' as an accessor.
node_modules/intern/lib/RemoteSuite.d.ts(6,5): error TS2610: 'executor' is defined as an accessor in class 'Suite', but is overridden here in 'RemoteSuite' as an instance property.

PR that sets skipLibCheck as true: #62