cf-https-connect: silence clang-tidy v21 false positive

content_encoding: another one

```
/Users/runner/work/curl/curl/lib/content_encoding.c:657:5: error: Out of bound access to memory preceding 'all' [clang-analyzer-security.ArrayBound,-warnings-as-errors]
  657 |     p[-2] = '\0';
      |     ^
```
Ref: https://github.com/curl/curl/actions/runs/17295803554/job/49093573741?pr=18422#step:11:40

mime.c

/Users/runner/work/curl/curl/lib/mime.c:1756:12: error: Out of bound access to memory after the end of the string literal [clang-analyzer-security.ArrayBound,-warnings-as-errors]
 1756 |     switch(contenttype[len]) {
      |            ^
https://github.com/curl/curl/actions/runs/17295955998/job/49094149140?pr=18422#step:11:127

ntlm.c

```
/Users/runner/work/curl/curl/lib/vauth/ntlm.c:414:5: error: Out of bound access to memory after the end of 'ntlmbuf' [clang-analyzer-security.ArrayBound,-warnings-as-errors]
  414 |     dest[2 * i] = (unsigned char)src[i];
      |     ^
```
https://github.com/curl/curl/actions/runs/17296813157/job/49097003881?pr=18422#step:11:157

ntlm.c more

/Users/runner/work/curl/curl/lib/vauth/ntlm.c:836:17: error: Out of bound access to memory after the end of 'ntlmbuf' [clang-analyzer-security.ArrayBound,-warnings-as-errors]
  836 |     unicodecpy(&ntlmbuf[size], host, hostlen / 2);
      |                 ^~~~~~~~~~~~~
https://github.com/curl/curl/actions/runs/17296961941/job/49097574789?pr=18422#step:11:157

silence bunch more

https://github.com/curl/curl/actions/runs/17297304862/job/49098795447?pr=18422

silence bunch more 2

more odd cases in vtls.c

lib/cf-https-connect.c

@@ -75,6 +75,7 @@ static void cf_hc_baller_reset(struct cf_hc_baller *b,
 
 static bool cf_hc_baller_is_active(struct cf_hc_baller *b)
 {
+  /* NOLINTNEXTLINE(clang-analyzer-security.ArrayBound) */
   return b->cf && !b->result;
 }